hy·a·cinth ['hī-ə-(,)sin(t)th, -sən(t)th] -n, adj

  1. a precious stone of the ancients sometimes held to be the sapphire
  2. a gem zircon or essonite
  3. a plant of the ancients held to be a lily, iris, larkspur, or gladiolus
  4. a bulbous perennial herb ( Hyacinthus orientalis) of the lily family that is native to the Mediterranean region but is widely grown for its dense spikes of fragrant flowers
  5. a light violet to moderate purple

Hy·a·cin·thus [,hī-ə-'sin(t)-thəs] -n

  1. a youth loved and accidentally killed by Apollo who memorializes him with a hyacinth growing from the youth's blood

Hy·a·des ['hī-ə-,dēz] -n pl

  1. a V-shaped cluster of stars in the head of the constellation Taurus held by the ancients to indicate rainy weather when they rise with the sun

hyal- -comb form

  1. glass : glassy : hyaline
    • hyal uronic acid

hy·a·line ['hī-ə-lən, -,līn] -adj

  1. transparent or nearly so and usu. homogeneous
  2. something (as the clear atmosphere) that is transparent
  3. any of several translucent nitrogenous substances related to chitin, found esp. around cells, and readily stained by eosin

hyaline cartilage -n

  1. translucent bluish-white cartilage with the cells embedded in an apparently homogeneous matrix present in joints and respiratory passages and forming most of the fetal skeleton

hy·a·lite ['hī-ə-,līt] -n

  1. a colorless opal that is clear as glass or sometimes translucent or whitish

hy·a·loid [-,lȯid] -adj

  1. glassy, transparent

hy·a·lo·plasm [hī-'a-lə-,pla-zəm, 'hī-ə-lō-] -n

  1. cytosol

hy·al·uron·ic acid [,hīl-yu̇-'rä-nik-, ,hī-əl-yu̇-] -n

  1. a viscous glycosaminoglycan chiefly of the matrix of tissues that occurs esp. in the vitreous humor, umbilical cord, synovial fluid, and loose connective tissue and serves esp. as a structural element and lubricant

hy·al·uron·i·dase [-'rä-nə-,dās, -,dāz] -n

  1. a mucolytic enzyme that facilitates the spread of fluids through tissues by lowering the viscosity of hyaluronic acid

hy·brid ['hī-brəd] -n, adj

  1. an offspring of two animals or plants of different races, breeds, varieties, species, or genera
  2. a person whose background is a blend of two diverse cultures or traditions
  3. something heterogeneous in origin or composition : composite
    • hybrid s of complementary DNA and RNA strands
    • a hybrid of medieval and Renaissance styles
  4. something (as a power plant, vehicle, or electronic circuit) that has two different types of components performing essentially the same function

hybrid computer -n

  1. a computer system consisting of a combination of analog and digital computer systems

hy·brid·ize ['hī-brə-,dīz] -vb, n

  1. to cause to produce hybrids : interbreed
  2. to produce hybrids

hy·brid·oma [,hī-brə-'dō-mə] -n

  1. a hybrid cell produced by the fusion of an antibody-producing lymphocyte with a tumor cell and used to culture continuously a specific monoclonal antibody

hybrid tea rose -n

  1. any of numerous moderately hardy cultivated hybrid bush roses grown esp. for their strongly recurrent bloom of large usu. scentless flowers called also hybrid tea

hybrid vigor -n

  1. heterosis

hyd -abbr

  1. hydraulics
  2. hydrostatics

hy·da·thode ['hī-də-,thōd] -n

  1. a specialized pore on the leaves of higher plants that functions in the exudation of water

hy·da·tid ['hī-də-təd, -,tid] -n

  1. the larval cyst of a tapeworm (genus Echinococcus) occurring as a fluid-filled sac containing daughter cysts in which scolices develop

hydr- -comb form

  1. water
    • hydr ous
    • hydro electric
  2. liquid
    • hydro kinetic
  3. hydrogen : containing or combined with hydrogen
    • hydro carbon
    • hydr oxyl
  4. hydroid
    • hydro medusa

Hy·dra ['hī-drə] -n

  1. a many-headed serpent or monster in Greek mythology that was slain by Hercules and each head of which when cut off was replaced by two others
  2. a multifarious evil not to be overcome by a single effort
  3. a southern constellation of great length that lies south of Cancer, Sextans, Corvus, and Virgo and is represented on old maps by a serpent
  4. any of numerous small tubular freshwater hydrozoan polyps ( Hydraand related genera) having at one end a mouth surrounded by tentacles

hy·drahead·ed [,hī-drə-'he-dəd] -adj

  1. having many centers or branches
    • a hydraheaded organization

hy·dral·azine [hī-'dra-lə-,zēn] -n

  1. a vasodilator C 8H 8N 4used in the form of its hydrochloride to treat hypertension

hy·dran·gea [hī-'drān-jə] -n

  1. any of a genus ( Hydrangea) of mostly shrubs having opposite leaves and showy clusters of usu. sterile white, pink, or bluish flowers that is either placed in the saxifrage family or the hydrangea family (Hydrangeaceae)

hy·drant ['hī-drənt] -n

  1. a discharge pipe with a valve and spout at which water may be drawn from a water main (as for fighting fires) called also fireplug
  2. faucet

hy·dranth ['hī-,dran(t)th] -n

  1. one of the feeding zooids of a hydroid colony

hy·drase ['hī-,drās, -,drāz] -n

  1. an enzyme that promotes the addition or removal of water to or from its substrate

hy·drate ['hī-,drāt] -n

  1. a compound formed by the union of water with some other substance

hydrate [hī-'drā-shən] -vb, n

  1. to cause to take up or combine with water or the elements of water
  2. to supply with ample fluid or moisture
    • hydrate s and softens the skin
  3. to become a hydrate

hy·drau·lic [hī-'drȯ-lik] -adj, adv

  1. operated, moved, or effected by means of water
  2. of or relating to hydraulics
    • hydraulic engineer
  3. of or relating to water or other liquid in motion
    • hydraulic erosion
  4. operated by the resistance offered or the pressure transmitted when a quantity of liquid (as water or oil) is forced through a comparatively small orifice or through a tube
    • hydraulic brakes
  5. hardening or setting under water
    • hydraulic cement

hy·drau·lics [hī-'drȯ-liks] -n pl but sing in constr

  1. a branch of science that deals with practical applications (as the transmission of energy or the effects of flow) of liquid (as water) in motion

hy·dra·zide ['hī-drə-,zīd] -n

  1. any of a class of compounds resulting from the replacement of hydrogen by an acid group in hydrazine or in one of its derivatives

hy·dra·zine ['hī-drə-,zēn] -n

  1. a colorless fuming corrosive strongly reducing liquid base N 2H 4used esp. in fuels for rocket and jet engines
  2. an organic base derived from this compound

hy·dra·zo·ic acid [,hī-drə-'zō-ik-] -n

  1. a colorless volatile poisonous explosive liquid HN 3that has a foul odor and yields explosive salts of heavy metals

hy·dric ['hī-drik] -adj

  1. characterized by, relating to, or requiring an abundance of moisture
    • a hydric habitat
    • a hydric plant

hy·dride ['hī-,drīd] -n

  1. a compound of hydrogen with a more electropositive element or group

hy·dril·la [hī-'dri-lə] -n

  1. a freshwater aquatic Asian plant ( Hydrilla verticillataof the Hydrocharitaceae family) that has small narrow leaves growing in whorls of three to eight around stems which become heavily branched near the water surface

hy·dri·od·ic acid [,hī-drē-'ä-dik-] -n

  1. an aqueous solution of hydrogen iodide HI that is a strong acid and a strong reducing agent

hy·dro ['hī-(,)drō] -n

  1. an establishment offering hydropathic treatment (as for weight loss) : health spa

hydro -n

  1. hydroelectric power

hy·dro·bi·ol·o·gy [,hī-drō-bī-'ä-lə-jē] -n, adj

  1. the biology of bodies or units of water
  2. limnology

hy·dro·bro·mic acid [,hī-drə-'brō-mik-] -n

  1. an aqueous solution of hydrogen bromide HBr that is a strong acid and a weak reducing agent and that is used esp. for making bromides

hy·dro·car·bon ['hī-drō-,kär-bən] -n

  1. an organic compound (as acetylene or butane) containing only carbon and hydrogen and often occurring in petroleum, natural gas, coal, and bitumens

hy·dro·cele ['hī-drə-,sēl] -n

  1. an accumulation of serous fluid in a saclike cavity (as the scrotum)

hy·dro·ce·phal·ic [,hī-drō-sə-'fa-lik] -adj, n

  1. relating to, characterized by, or affected with hydrocephalus

hy·dro·ceph·a·lus [-'se-fə-ləs] -n

  1. an abnormal increase in the amount of cerebrospinal fluid within the cranial cavity that is accompanied by expansion of the cerebral ventricles, enlargement of the skull and esp. the forehead, and atrophy of the brain

hy·dro·chlo·ric acid [,hī-drə-'klȯr-ik-] -n

  1. an aqueous solution of hydrogen chloride HCl that is a strong corrosive irritating acid, is normally present in dilute form in gastric juice, and is widely used in industry and in the laboratory

hy·dro·chlo·ride [-'klȯr-,īd] -n

  1. a chemical complex composed of an organic base (as an alkaloid) in association with hydrogen chloride

hy·dro·chlo·ro·fluo·ro·car·bon [-,klȯr-ō-,flȯr-ō-'kär-bən, -,flu̇r-] -n

  1. any of several simple gaseous compounds that contain carbon, chlorine, fluorine, and hydrogen

hy·dro·chlo·ro·thi·a·zide [-,klȯr-ə-'thī-ə-,zīd] -n

  1. a diuretic and antihypertensive drug C 7H 8ClN 3O 4S 2

hy·dro·col·loid [,hī-drə-'kä-,lȯid] -n, adj

  1. a substance that yields a gel with water

hy·dro·cor·ti·sone [-'kȯr-tə-,sōn, -,zōn] -n

  1. cortisol
  2. cortisol used pharmaceutically

hy·dro·crack·ing ['hī-drə-,kra-kiŋ] -n, vt

  1. the cracking of hydrocarbons in the presence of hydrogen

hy·dro·cy·an·ic acid [,hī-drō-sī-'a-nik-] -n

  1. an aqueous solution of hydrogen cyanide HCN that is a poisonous weak acid and is used chiefly in fumigating and in organic synthesis

hy·dro·dy·nam·ic [-dī-'na-mik] -adj, adv

  1. of, relating to, or involving principles of hydrodynamics

hy·dro·dy·nam·ics [-miks] -n pl but sing in constr, n

  1. a branch of physics that deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in motion relative to them

hy·dro·elec·tric [,hī-drō-i-'lek-trik] -adj, adv, n

  1. of or relating to production of electricity by waterpower
    • constructed a hydroelectric power plant at the dam site

hy·dro·flu·or·ic acid [,hī-drō-'flȯr-ik, -'flu̇r-] -n

  1. an aqueous solution of hydrogen fluoride HF that is a weak poisonous acid, that attacks silica and silicates, and that is used esp. in finishing and etching glass

hy·dro·fluo·ro·car·bon [-,flȯr-ō-'kär-bən, -,flu̇r-] -n

  1. any of several simple gaseous compounds that contain carbon, fluorine, and hydrogen

hy·dro·foil ['hī-drə-,fȯi(-ə)l] -n

  1. a body similar to an airfoil but designed for action in or on water
  2. a motorboat that has metal plates or fins attached by struts fore and aft for lifting the hull clear of the water as speed is attained

hy·dro·gel ['hī-drə-,jel] -n

  1. a gel composed usu. of one or more polymers suspended in water

hy·dro·gen ['hī-drə-jən, -dər-] -n, adj

  1. a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used esp. in synthesis

hy·drog·e·nase [hī-'drä-jə-,nās, -,nāz] -n

  1. an enzyme of various microorganisms that promotes the formation and utilization of gaseous hydrogen

hy·dro·ge·nate [hī-'drä-jə-,nāt, 'hī-drə-] -vt, n

  1. to combine or treat with or expose to hydrogen
  2. to add hydrogen to the molecule of (an unsaturated organic compound)

hydrogen bomb -n

  1. a bomb whose violent explosive power is due to the sudden release of atomic energy resulting from the fusion of light nuclei (as of hydrogen atoms) at very high temperature and pressure to form helium nuclei

hydrogen bond -n

  1. an electrostatic attraction between a hydrogen atom in one polar molecule (as of water) and a small electronegative atom (as of oxygen, nitrogen, or fluorine) in usu. another molecule of the same or a different polar substance

hydrogen bromide -n

  1. a colorless irritating gas HBr that fumes in moist air and yields hydrobromic acid when dissolved in water

hydrogen chloride -n

  1. a colorless pungent poisonous gas HCl that fumes in moist air and yields hydrochloric acid when dissolved in water

hydrogen cyanide -n

  1. a poisonous usu. gaseous compound HCN that has the odor of bitter almonds
  2. hydrocyanic acid

hydrogen fluoride -n

  1. a colorless corrosive fuming usu. gaseous compound HF that yields hydrofluoric acid when dissolved in water

hydrogen iodide -n

  1. an acrid colorless gas HI that fumes in moist air and yields hydriodic acid when dissolved in water

hydrogen ion -n

  1. the cation H of acids consisting of a hydrogen atom whose electron has been transferred to the anion of the acid
  2. hydronium

hydrogen peroxide -n

  1. an unstable compound H 2O 2used esp. as an oxidizing and bleaching agent, an antiseptic, and a propellant

hydrogen sulfide -n

  1. a flammable poisonous gas H 2S that has an odor suggestive of rotten eggs and is found esp. in many mineral waters and in putrefying matter

hy·dro·ge·ol·o·gy [,hī-drō-jē-'ä-lə-jē] -n

  1. a branch of geology concerned with the occurrence, use, and functions of surface water and groundwater
  2. the phenomena dealt with in hydrogeology

hy·dro·graph·ic [,hī-drə-'gra-fik] -adj, n

  1. of or relating to the characteristic features (as flow or depth) of bodies of water
  2. relating to the charting of bodies of water

hy·droid ['hī-,drȯid] -adj

  1. of or relating to a hydrozoan
  2. resembling a typical hydra

hydroid -n

  1. hydrozoan
  2. a hydrozoan polyp as distinguished from a hydrozoan jellyfish

hy·dro·ki·net·ic [,hī-drō-kə-'ne-tik, -(,)kī-] -adj

  1. of or relating to the motions of fluids or the forces which produce or affect such motions

hy·dro·lase ['hī-drə-,lās, -,lāz] -n

  1. a hydrolytic enzyme

hydrologic cycle -n

  1. the sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration called also hydrological cycle

hy·drol·o·gy [hī-'drä-lə-jē] -n, adj, adv

  1. a science dealing with the properties, distribution, and circulation of water on and below the earth's surface and in the atmosphere

hy·dro·ly·sate [hī-'drä-lə-,sāt] -n

  1. a product of hydrolysis

hy·dro·ly·sis [hī-'drä-lə-səs] -n, adj, adv

  1. a chemical process of decomposition involving the splitting of a bond and the addition of the hydrogen cation and the hydroxide anion of water

hy·dro·lyze ['hī-drə-,līz] -vb, adj

  1. to subject to hydrolysis
  2. to undergo hydrolysis

hy·dro·mag·net·ic [,hī-drō-mag-'ne-tik] -adj

  1. magnetohydrodynamic

hy·dro·man·cy ['hī-drə-,man(t)-sē] -n

  1. divination by the appearance or motion of liquids (as water)

hy·dro·mas·sage [,hī-drō-mə-'säzh, -'säj] -n

  1. a massage using jets of water
  2. spa

hy·dro·me·chan·i·cal [,hī-drō-mi-'ka-ni-kəl] -adj, n pl but sing in constr

  1. relating to a branch of mechanics that deals with the equilibrium and motion of fluids and of solid bodies immersed in them

hy·dro·me·du·sa [,hī-drō-mi-'dü-sə, -'dyü-, -zə] -n

  1. a jellyfish (as of the orders Anthomedusae and Leptomedusae) produced as a bud from a hydroid

hy·dro·met·al·lur·gy [,hī-drō-'me-tə-,lər-jē] -n, adj

  1. the treatment of ores by wet processes (as leaching)

hy·dro·me·te·or [,hī-drō-'mē-tē-ər, -tē-,ȯr] -n

  1. a product (as rain) formed by the condensation of atmospheric water vapor

hy·dro·me·te·o·rol·o·gy [-,mē-tē-ə-'rä-lə-jē] -n, adj

  1. a branch of meteorology that deals with water in the atmosphere esp. as precipitation

hy·drom·e·ter [hī-'drä-mə-tər] -n, adj

  1. an instrument for determining the specific gravity of a liquid (as battery acid or an alcohol solution) and hence its strength

hy·dro·mor·phic [,hī-drə-'mȯr-fik] -adj

  1. developed in the presence of an excess of moisture which tends to suppress aerobic factors in soil-building

hy·dron·ic [hī-'drä-nik] -adj, adv

  1. of, relating to, or being a system of heating or cooling that involves transfer of heat by a circulating fluid (as water or vapor) in a closed system of pipes

hy·dro·ni·um [hī-'drō-nē-əm] -n

  1. a hydrated hydrogen ion H 3O

hy·drop·a·thy [hī-'drä-pə-thē] -n, adj

  1. a method of treating disease by copious and frequent use of water both externally and internally

hy·dro·per·ox·ide [,hī-drō-pə-'räk-,sīd] -n

  1. a compound containing an O 2H group

hy·dro·phane ['hī-drə-,fān] -n

  1. a semitranslucent opal that becomes translucent or transparent on immersion in water

hy·dro·phil·ic [,hī-drə-'fi-lik] -adj, n

  1. of, relating to, or having a strong affinity for water
    • hydrophilic proteins

hy·dro·pho·bia [,hī-drə-'fō-bē-ə] -n

  1. rabies
  2. a morbid dread of water

hy·dro·pho·bic [-'fō-bik] -adj, n

  1. of, relating to, or suffering from hydrophobia
  2. lacking affinity for water

hy·dro·phone ['hī-drə-,fōn] -n

  1. an instrument for listening to sound transmitted through water

hy·dro·phyte [-,fīt] -n, adj

  1. a plant that grows either partly or totally submerged in water
  2. a plant growing in waterlogged soil

hy·dro·plane ['hī-drə-,plān] -n

  1. a powerboat designed for racing that skims the surface of the water
  2. seaplane

hydroplane -vi

  1. to skim on water
  2. to skid on a wet surface (as pavement) because a film of water on the surface causes the tires to lose contact with it

hy·dro·pon·ics [,hī-drə-'pä-niks] -n pl but sing in constr, adj, adv

  1. the growing of plants in nutrient solutions with or without an inert medium (as soil) to provide mechanical support

hy·dro·pow·er ['hī-drə-,pau̇(-ə)r] -n

  1. hydroelectric power

hy·dro·qui·none [,hī-drō-kwi-'nōn, -'kwi-,nōn] -n

  1. a white crystalline strongly reducing phenol C 6H 6O 2used esp. as a photographic developer, as an antioxidant and stabilizer, and in medicine to remove pigmentation from hyperpigmented areas of skin

hy·dro·sere ['hī-drə-,sir] -n

  1. an ecological sere originating in an aquatic habitat

hy·dro·sol ['hī-drə-,säl, -,sȯl] -n, adj

  1. a sol in which the liquid is water

hy·dro·space [-,spās] -n

  1. the regions beneath the surface of the ocean

hy·dro·sphere [-,sfir] -n, adj

  1. the aqueous vapor of the atmosphere
  2. the aqueous envelope of the earth including bodies of water and aqueous vapor in the atmosphere

hy·dro·stat·ic [,hī-drə-'sta-tik] -adj, adv

  1. of or relating to fluids at rest or to the pressures they exert or transmit

hy·dro·stat·ics [-tiks] -n pl but sing in constr

  1. a branch of physics that deals with the characteristics of fluids at rest and esp. with the pressure in a fluid or exerted by a fluid on an immersed body

hy·dro·ther·a·py [,hī-drə-'ther-ə-pē] -n

  1. the therapeutic use of water (as in a whirlpool bath)

hy·dro·ther·mal [,hī-drə-'thər-məl] -adj, adv

  1. of or relating to hot water used esp. of the formation of minerals by hot solutions rising from a cooling magma

hydrothermal vent -n

  1. a fissure in the ocean floor esp. at or near a mid-ocean ridge from which mineral-rich superheated water issues

hy·dro·tho·rax [-'thȯr-,aks] -n

  1. an excess of serous fluid in the pleural cavity
  2. an effusion resulting from failing circulation (as in heart disease or from lung infection)

hy·drot·ro·pism [hī-'drä-trə-,pi-zəm] -n, adj

  1. a tropism (as in plant roots) in which water or water vapor is the orienting factor

hy·drous ['hī-drəs] -adj

  1. containing water usu. in chemical association (as in hydrates)

hy·drox·ide [hī-'dräk-,sīd] -n

  1. the monovalent anion OH consisting of one atom of hydrogen and one of oxygen called also hydroxide ion
  2. an ionic compound of hydroxide with an element or group

hy·droxy [hī-'dräk-sē] -adj

  1. being or containing hydroxyl
  2. containing hydroxyl esp. in place of hydrogen usu. used in combination
    • hydroxy acetic acid

hy·droxy·ap·a·tite [hī-,dräk-sē-'a-pə-,tīt] -n

  1. a complex phosphate of calcium Ca 5(PO 4) 3OH that occurs as a mineral and is the chief structural element of vertebrate bone

hy·droxy·bu·tyr·ic acid [hī-,dräk-sē-byu̇-'tir-ik-] -n

  1. a hydroxy derivative C 4H 8O 3of butyric acid that is excreted in increased quantities in the urine in diabetes

hy·drox·yl [hī-'dräk-səl] -n, adj

  1. the chemical group, ion, or radical OH that consists of one atom of hydrogen and one of oxygen and is neutral or negatively charged
  2. hydroxide

hy·drox·yl·amine [hī-'dräk-sə-lə-,mēn, ,hī-,dräk-'si-lə-,mēn] -n

  1. a colorless odorless nitrogenous base NH 3O that resembles ammonia in its reactions but is less basic and that is used esp. as a reducing agent

hy·drox·y·lase [hī-'dräk-sə-,lās, -,lāz] -n

  1. any of a group of enzymes that catalyze oxidation reactions in which one of the two atoms of molecular oxygen is incorporated into the substrate and the other is used to oxidize NADH or NADPH

hy·drox·yl·ate [hī-'dräk-sə-,lāt] -vt, n

  1. to introduce hydroxyl into

hy·droxy·pro·line [hī-,dräk-sē-'prō-,lēn] -n

  1. an amino acid C 5H 9NO 3that occurs naturally as a constituent of collagen

hy·droxy·tryp·ta·mine [-'trip-tə-,mēn] -n

  1. serotonin usu. preceded by the numeral 5
    • 5- hydroxytryptamine

hy·droxy·urea [-yu̇-'rē-ə] -n

  1. a drug CH 4N 2O 2used to treat some forms of leukemia, melanoma, and malignant tumors

hy·droxy·zine [hī-'dräk-sə-,zēn] -n

  1. a compound C 21H 27ClN 2O 2used as an antihistamine and tranquilizer

hy·dro·zo·an [,hī-drə-'zō-ən] -n, adj

  1. any of a class (Hydrozoa) of coelenterates that includes solitary and colonial polyps and jellyfishes having no stomodeum or gastric tentacles

hy·e·na [hī-'ē-nə] -n, adj

  1. any of several large strong nocturnal carnivorous Old World mammals (family Hyaenidae) that usu. feed as scavengers

Hy·ge·ia [hī-'jē-ə] -n

  1. the goddess of health in Greek mythology

hy·giene ['hī-,jēn also hī-'] -n

  1. a science of the establishment and maintenance of health
  2. conditions or practices (as of cleanliness) conducive to health

hy·gien·ic [,hī-'jē-nik, -'je- also -jē-'e-nik] -adj, adv

  1. of or relating to hygiene
  2. having or showing good hygiene
    • hygienic conditions
  3. antiseptic
    • sweetly hygienic production...comic in an entirely innocuous way -- J. W. Aldridge
  4. antiseptic
    • a hygienic view of national realities and moral imperatives -- I. L. Horowitz

hy·gien·ics [,hī-'jē-niks, -'je- also -jē-'e-niks] -n pl but sing in constr

  1. hygiene

hygr- -comb form

  1. humidity : moisture
    • hygro phyte

hy·gro·graph ['hī-grə-,graf] -n

  1. an instrument for recording automatically variations in atmospheric humidity

hy·grom·e·ter [hī-'grä-mə-tər] -n, adj

  1. any of several instruments for measuring the humidity of the atmosphere

hy·groph·i·lous [hī-'grä-fə-ləs] -adj

  1. living or growing in moist places

hy·gro·scop·ic [,hī-grə-'skä-pik] -adj, n

  1. readily taking up and retaining moisture
  2. taken up and retained under some conditions of humidity and temperature
    • hygroscopic water in clay

hying ['hī] -vb

(variant of hie)

  1. to go quickly : hasten
  2. to cause (oneself) to go quickly

Hyk·sos ['hik-,säs, -,sōs] -adj

  1. of or relating to a Semite dynasty that ruled Egypt from about the 18th to the 16th century b.c.

hy·lo·zo·ism [,hī-lə-'zō-,i-zəm] -n, adj

  1. a doctrine held esp. by early Greek philosophers that all matter has life

hy·men ['hī-mən] -n, adj

  1. a fold of mucous membrane partly closing the orifice of the vagina

Hymen -n

  1. the Greek god of marriage

hy·me·ne·al [,hī-mə-'nē-əl] -adj, adv

  1. nuptial

hymeneal -n

  1. nuptials
  2. a wedding hymn

hy·me·ni·um [hī-'mē-nē-əm] -n

  1. a spore-bearing layer in fungi

hy·me·nop·ter·an [,hī-mə-'näp-tə-rən] -n, adj

  1. any of an order (Hymenoptera) of highly specialized insects with complete metamorphosis that include the bees, wasps, ants, ichneumon flies, sawflies, gall wasps, and related forms, often associate in large colonies with complex social organization, and have usu. four membranous wings and the abdomen generally borne on a slender pedicel

hy·me·nop·ter·on [-tə-,rän, -rən] -n

  1. hymenopteran

hymn ['him] -n, adj

  1. a song of praise to God
  2. a metrical composition adapted for singing in a religious service
  3. a song of praise or joy
  4. something resembling a hymn : paean
  5. to praise or worship in or as if in hymns
    • the heroes hymn ed in this book
  6. to sing a hymn

hym·nal ['him-nəl] -n

  1. a collection of church hymns

hym·na·ry ['him-nə-rē] -n

  1. hymnal

hymn·book ['him-,bu̇k] -n

  1. hymnal

hym·no·dy ['him-nə-dē] -n

  1. hymn singing
  2. hymn writing
  3. the hymns of a time, place, or church

hym·nol·o·gy [him-'nä-lə-jē] -n

  1. hymnody
  2. the study of hymns

hy·oid ['hī-,ȯid] -adj

  1. of or relating to the hyoid bone

hyoid bone -n

  1. a U-shaped bone or complex of bones that is situated between the base of the tongue and the larynx and that supports the tongue, the larynx, and their muscles called also hyoid

hy·o·scine ['hī-ə-,sēn] -n

  1. scopolamine
  2. the levorotatory form of scopolamine

hy·o·scy·a·mine [,hī-ə-'sī-ə-,mēn] -n

  1. a poisonous crystalline alkaloid C 17H 23NO 3of which atropine is a racemic mixture
  2. its levorotatory form found esp. in the plants belladonna and henbane and used similarly to atropine

hyp -abbr

  1. hypothesis; hypothetical

hyp·abys·sal [,hi-pə-'bi-səl, ,hī-] -adj, adv

  1. of or relating to a fine-grained igneous rock usu. formed at a moderate distance below the surface

hy·pae·thral [hī-'pē-thrəl] -adj

  1. having a roofless central space
    • hypaethral temple
  2. open to the sky

hy·pal·la·ge [hī-'pa-lə-jē, hi-] -n

  1. an interchange of two elements in a phrase or sentence from a more logical to a less logical relationship (as in a mind is a terrible thing to waste for to waste a mind is a terrible thing)

hy·pan·thi·um [hī-'pan(t)-thē-əm] -n

  1. an enlargement of the floral receptacle bearing on its rim the stamens, petals, and sepals and often enlarging and surrounding the fruits (as in the rose hip)

hype ['hīp] -n

  1. a narcotics addict
  2. hypodermic
  3. stimulate, enliven usu. used with up
    • hyping herself up for the game
  4. increase
  5. put on, deceive
  6. to promote or publicize extravagantly
    • hyping this fall's TV lineup
  7. deception, put-on
  8. publicity
  9. promotional publicity of an extravagant or contrived kind
    • all the hype before the boxing match
  10. excellent, cool

hy·per ['hī-pər] -adj

  1. high-strung, excitable
  2. highly excited
  3. extremely active

hyper- -prefix

  1. above : beyond : super-
    • hyper market
  2. excessively
    • hyper sensitive
  3. excessive
    • hyper emia
  4. that is or exists in a space of more than three dimensions
    • hyper space
  5. bridging points within an entity (as a database or network) nonsequentially
    • hyper text

hy·per·acid·i·ty [,hī-pər-ə-'si-də-tē] -n, adj

  1. the condition of containing more than the normal amount of acid

hy·per·ac·tive [,hī-pər-'ak-tiv] -adj, n

  1. affected with or exhibiting hyperactivity
  2. more active than is usual or desirable
  3. intricately or elaborately designed or detailed

hy·per·ac·tiv·i·ty [-,ak-'ti-və-tē] -n

  1. the state or condition of being excessively or pathologically active
  2. attention deficit disorder

hyperaesthesia [,hī-pər-es-'thē-zh(ē-)ə] -n, adj

(variant of hyperesthesia)

  1. unusual or pathological sensitivity of the skin or of a particular sense

hy·per·al·i·men·ta·tion [,hī-pər-,a-lə-mən-'tā-shən] -n

  1. the administration of nutrients by intravenous feeding esp. to patients who cannot ingest food through the alimentary tract

hy·per·bar·ic [,hī-pər-'ber-ik, -'ba-rik] -adj, adv

  1. of, relating to, or utilizing greater than normal pressure esp. of oxygen
    • a hyperbaric chamber
    • hyperbaric medicine

hy·per·bo·la [hī-'pər-bə-lə] -n

  1. a plane curve generated by a point so moving that the difference of the distances from two fixed points is a constant : a curve formed by the intersection of a double right circular cone with a plane that cuts both halves of the cone

hy·per·bo·le [hī-'pər-bə-(,)lē] -n

  1. extravagant exaggeration (as mile-high ice-cream cones)

hy·per·bol·ic [,hī-pər-'bä-lik] -adj, adv

  1. of, relating to, or marked by hyperbole

hyperbolic -adj

  1. of, relating to, or being analogous to a hyperbola
  2. of, relating to, or being a space in which more than one line parallel to a given line passes through a point
    • hyperbolic geometry

hyperbolic function -n

  1. any of a set of six functions analogous to the trigonometric functions but related to the hyperbola in a way similar to that in which the trigonometric functions are related to a circle

hyperbolic paraboloid -n

  1. a saddle-shaped quadric surface whose sections by planes parallel to one coordinate plane are hyperbolas while those sections by planes parallel to the other two are parabolas if proper orientation of the coordinate axes is assumed

hy·per·bo·lize [hī-'pər-bə-,līz] -vb

  1. to indulge in hyperbole
  2. to exaggerate to a hyperbolic degree

hy·per·bo·loid [-,lȯid] -n, adj

  1. a quadric surface whose sections by planes parallel to one coordinate plane are ellipses while those sections by planes parallel to the other two are hyperbolas if proper orientation of the axes is assumed

hy·per·bo·re·an [,hī-pər-'bȯr-ē-ən, -(,)pər-bə-'rē-ən] -n

  1. a member of a people held by the ancient Greeks to live beyond the north wind in a region of perpetual sunshine
  2. an inhabitant of a cool northern climate

hyperborean -adj

  1. of or relating to an extreme northern region : frozen
  2. of or relating to any of the arctic peoples

hy·per·cal·ce·mia [,hī-pər-,kal-'sē-mē-ə] -n, adj

  1. an excess of calcium in the blood

hy·per·cap·nia [-'kap-nē-ə] -n, adj

  1. the presence of excessive amounts of carbon dioxide in the blood

hy·per·cat·a·lex·is [-,ka-tə-'lek-səs] -n, adj

  1. the occurrence of an additional syllable after the final complete foot or dipody in a line of verse

hy·per·charge ['hī-pər-,chärj] -n

  1. a quantum characteristic of a group of subatomic particles governed by the strong force that is related to strangeness and is represented by a number equal to twice the average value of the electric charge of the group

hy·per·cho·les·ter·ol·emia [,hī-pər-kə-,les-tə-rə-'lē-mē-ə] -n, adj

  1. the presence of excess cholesterol in the blood

hy·per·cor·rect [,hī-pər-kə-'rekt] -adj, n, adv

  1. of, relating to, or characterized by the production of a nonstandard linguistic form or construction on the basis of a false analogy (as badly in my eyes have gone badly and widely in open widely)

hy·per·crit·ic [,hī-pər-'kri-tik] -n

  1. a carping or unduly censorious critic

hy·per·crit·i·cal [-'kri-ti-kəl] -adj, adv

  1. meticulously or excessively critical

hy·per·cube ['hī-pər-,kyüb] -n

  1. a geometric figure (as a tesseract) in Euclidean space of ndimensions that is analogous to a cube in three dimensions
  2. a computer architecture in which each processor is connected to nothers based on analogy to a hypercube of ndimensions

hy·per·drive ['hī-pər-,drīv] -n

  1. a state of extremely heightened activity
    • the promotions department went into hyperdrive

hy·per·emia [,hī-pər-'ē-mē-ə] -n, adj

  1. excess of blood in a body part : congestion

hy·per·es·the·sia [,hī-pər-es-'thē-zh(ē-)ə] -n, adj

  1. unusual or pathological sensitivity of the skin or of a particular sense

hy·per·eu·tec·tic [,hī-pər-yu̇-'tek-tik] -adj

  1. hypereutectoid

hy·per·eu·tec·toid [-,tȯid] -adj

  1. containing the minor component in excess of that contained in the eutectoid

hy·per·ex·tend [,hī-pər-ik-'stend] -vt, n

  1. to extend so that the angle between bones of a joint is greater than normal
    • a hyperextend ed elbow
  2. to extend (as a body part) beyond the normal range of motion
    • hyperextend ed her neck

hy·per·fine ['hī-pər-,fīn] -adj

  1. being or relating to a fine-structure multiplet occurring in an atomic spectrum that is due to interaction between electrons and nuclear spin

hy·per·fo·cal distance [,hī-pər-'fō-kəl-] -n

  1. the nearest distance upon which a photographic lens may be focused to produce satisfactory definition at infinity

hy·per·ga·my [hī-'pər-gə-mē] -n

  1. marriage into an equal or higher caste or social group

hy·per·geo·met·ric distribution [,hī-pər-,jē-ə-'me-trik-] -n

  1. a probability function f(x)that gives the probability of obtaining exactly xelements of one kind and n xelements of another if nelements are chosen at random without replacement from a finite population containing Nelements of which Mare of the first kind and N Mare of the second kind and that has the form

hy·per·gly·ce·mia [,hī-pər-glī-'sē-mē-ə] -n, adj

  1. excess of sugar in the blood

hy·per·gol·ic [,hī-pər-'gä-lik] -adj, adv

  1. igniting upon contact of components without external aid (as a spark)
  2. of, relating to, or using hypergolic fuel

hy·per·hi·dro·sis [,hī-pər-hī-'drō-səs] -n

  1. generalized or local excessive sweating

hy·per·in·fla·tion [,hī-pər-in-'flā-shən] -n, adj

  1. inflation growing at a very high rate in a very short time
  2. a period of hyperinflation

hy·per·in·su·lin·ism [,hī-pər-'in(t)-s(ə-)lə-,ni-zəm] -n

  1. the presence of excess insulin in the body resulting in hypoglycemia

Hy·pe·ri·on [hī-'pir-ē-ən] -n

  1. a Titan and the father of Eos, Selene, and Helios

hy·per·ir·ri·ta·bil·i·ty [,hī-pər-,ir-ə-tə-'bi-lə-tē] -n, adj

  1. abnormally great or uninhibited response to stimuli

hy·per·ker·a·to·sis [,hī-pər-,ker-ə-'tō-səs] -n, adj

  1. hypertrophy of the corneous layer of the skin

hy·per·ki·ne·sia [-kə-'nē-zh(ē-)ə, -kī-] -n

  1. hyperkinesis

hy·per·ki·ne·sis [-'nē-səs] -n

  1. abnormally increased and sometimes uncontrollable activity or muscular movements
  2. a condition esp. of childhood characterized by hyperactivity

hy·per·ki·net·ic [-'ne-tik] -adj

  1. of, relating to, or affected with hyperkinesis or hyperactivity
    • the hyperkinetic child
  2. characterized by fast-paced or frenetic activity
    • a hyperkinetic movie

hy·per·link ['hī-pər-,liŋk] -n, vt

  1. an electronic link providing direct access from one distinctively marked place in a hypertext or hypermedia document to another in the same or a different document

hy·per·li·pe·mia [,hī-pər-lī-'pē-mē-ə] -n, adj

  1. hyperlipidemia

hy·per·lip·id·emia [-,li-pə-'dē-mē-ə] -n

  1. the presence of excess fat or lipids in the blood

hy·per·mar·ket ['hī-pər-,mär-kət] -n

  1. a very large store that carries products found in a supermarket as well as merchandise commonly found in department stores

hy·per·me·dia [-,mē-dē-ə] -n

  1. a database format similar to hypertext in which text, sound, or video images related to that on a display can be accessed directly from the display

hy·per·me·ter [hī-'pər-mə-tər] -n, adj

  1. a verse marked by hypercatalexis
  2. a period comprising more than two or three cola

hy·per·me·tro·pia [,hī-pər-mi-'trō-pē-ə] -n, adj

  1. hyperopia

hy·perm·ne·sia [,hī-(,)pərm-'nē-zh(ē-)ə] -n, adj

  1. abnormally vivid or complete memory or recall of the past

hy·per·on ['hī-pə-,rän] -n

  1. an elementary particle of the baryon group having greater mass than a nucleon

hy·per·opia [,hī-pə-'rō-pē-ə] -n, adj

  1. a condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects called also farsightedness

hy·per·os·to·sis [,hī-pər-,äs-'tō-səs] -n, adj

  1. excessive growth or thickening of bone tissue

hy·per·par·a·site [,hī-pər-'per-ə-,sīt, -'pa-rə-] -n, adj

  1. a parasite that is parasitic upon another parasite

hy·per·para·thy·roid·ism [-,per-ə-'thī-,rȯi-,di-zəm, -,pa-rə-] -n

  1. the presence of excess parathyroid hormone in the body resulting in disturbance of calcium metabolism with increase in serum calcium and decrease in inorganic phosphorus, loss of calcium from bone, and renal damage with frequent kidney-stone formation

hy·per·pha·gia [-'fā-j(ē-)ə] -n, adj

  1. abnormally increased appetite for consumption of food frequently associated with injury to the hypothalamus

hy·per·pi·tu·ita·rism [-pə-'tü-ə-tə-,ri-zəm, -'tü-ə-,tri-, -'tyü-] -n, adj

  1. excessive production of growth hormones by the pituitary gland

hy·per·plane ['hī-pər-,plān] -n

  1. a figure in hyperspace corresponding to a plane in ordinary space

hy·per·pla·sia [,hī-pər-'plā-zh(ē-)ə] -n, adj

  1. an abnormal or unusual increase in the elements composing a part (as cells composing a tissue)

hy·per·ploid ['hī-pər-,plȯid] -adj, n

  1. having a chromosome number slightly greater than an exact multiple of the monoploid number

hy·per·pnea [,hī-pər-'nē-ə, -,pərp-'nē-] -n, adj

  1. abnormally rapid or deep breathing

hy·per·po·lar·ize [,hī-pər-'pō-lə-,rīz] -vt, n

  1. to produce an increase in potential difference across (a biological membrane)
  2. to undergo or produce an increase in potential difference across something

hy·per·py·rex·ia [-pī-'rek-sē-ə] -n

  1. exceptionally high fever (as in a particular disease)

hy·per·re·al·ism [,hī-pər-'rē-ə-,li-zəm, -'rēl-,i-] -n, adj

  1. realism in art characterized by depiction of real life in an unusual or striking manner

hy·per·sen·si·tive [,hī-pər-'sen(t)-s(ə-)tiv] -adj, n

  1. excessively or abnormally sensitive
  2. abnormally susceptible physiologically to a specific agent (as a drug or antigen)

hy·per·sex·u·al [-'sek-sh(ə-)wəl, -'sek-shəl] -adj, n

  1. exhibiting unusual or excessive concern with or indulgence in sexual activity

hy·per·son·ic [-'sä-nik] -adj, adv

  1. of or relating to speed five or more times that of sound in air
  2. moving, capable of moving, or utilizing air currents that move at hypersonic speed
    • hypersonic wind tunnel

hy·per·space ['hī-pər-,spās] -n

  1. space of more than three dimensions
  2. a fictional space held to support extraordinary events (as travel faster than the speed of light)

hy·per·sthene ['hī-pərs-,thēn] -n, adj

  1. an orthorhombic grayish or greenish black or dark brown pyroxene

hy·per·sur·face ['hī-pər-,sər-fəs] -n

  1. a figure that is the analogue in hyperspace of a surface in three-dimensional space

hy·per·ten·sion [,hī-pər-'ten(t)-shən] -n

  1. abnormally high blood pressure and esp. arterial blood pressure
  2. the systemic condition accompanying high blood pressure

hy·per·ten·sive [,hī-pər-'ten(t)-siv] -adj

  1. affected with or caused by hypertension

hypertensive -n

  1. an individual affected with hypertension

hy·per·text ['hī-pər-,tekst] -n, adj

  1. a database format in which information related to that on a display can be accessed directly from the display
  2. material (as text) in this format

hypertext markup language -n

  1. HTML

hypertext transfer protocol -n

  1. a communications protocol governing the exchange of data (as HTML files) esp. on the World Wide Web called also hypertext transport protocol

hy·per·ther·mia [,hī-pər-'thər-mē-ə] -n, adj

  1. exceptionally high fever esp. when induced artificially for therapeutic purposes

hy·per·ther·mo·phile [,hī-pər-'thər-mə-,fī(-ə)l] -n, adj

  1. an organism that lives in extremely hot environments (as hot springs) with temperatures around the boiling point of water

hy·per·thy·roid [-'thī-,rȯid] -adj

  1. of, relating to, or affected with hyperthyroidism

hy·per·thy·roid·ism [-,rȯi-,di-zəm] -n

  1. excessive functional activity of the thyroid gland
  2. the resulting condition marked esp. by increased metabolic rate, enlargement of the thyroid gland, rapid heart rate, and high blood pressure

hy·per·to·nia [,hī-pər-'tō-nē-ə] -n

  1. the condition of exhibiting excessive muscular tone or tension

hy·per·ton·ic [-'tä-nik] -adj

  1. exhibiting excessive tone or tension
    • a hypertonic baby
    • a hypertonic bladder
  2. having a higher osmotic pressure than a surrounding medium or a fluid under comparison

hy·per·to·nic·i·ty [-tə-'ni-sə-tē] -n

  1. the condition of being hypertonic
  2. hypertonia

hy·per·tro·phy [hī-'pər-trə-fē] -n, adj

  1. excessive development of an organ or part
  2. increase in bulk (as by thickening of muscle fibers) without multiplication of parts
  3. exaggerated growth or complexity

hypertrophy -vi

  1. to undergo hypertrophy

hy·per·ur·ban·ism [,hī-pər-'ər-bə-,ni-zəm] -n

  1. use of hypercorrect forms in language
  2. such a form

hy·per·uri·ce·mia [,hī-pər-,yu̇r-ə-'sē-mē-ə] -n

  1. excess uric acid in the blood

hy·per·var·i·able [,hī-pər-'ver-ē-ə-bəl] -adj

  1. relating to or being any of the relatively short extremely variable polypeptide chain segments in the light chain or heavy chain of an antibody
  2. relating to, containing, or being a highly variable nucleotide sequence

hy·per·ve·loc·i·ty [-və-'lä-sə-tē, -'läs-tē] -n

  1. a high or relatively high velocity (as thousands of feet or meters per second)

hy·per·ven·ti·late [,hī-pər-'ven-tə-,lāt] -vi

  1. to breathe rapidly and deeply : undergo hyperventilation

hy·per·ven·ti·la·tion [-,ven-tə-'lā-shən] -n

  1. excessive rate and depth of respiration leading to abnormal loss of carbon dioxide from the blood

hy·per·vi·ta·min·osis [-,vī-tə-mə-'nō-səs] -n

  1. an abnormal state resulting from excessive intake of one or more vitamins

hy·pha ['hī-fə] -n, adj

  1. one of the threads that make up the mycelium of a fungus, increase by apical growth, and are transversely septate or nonseptate

hy·phen ['hī-fən] -n, adj

  1. a punctuation mark - used esp. to divide or to compound words, word elements, or numbers

hyphen -vt

  1. hyphenate

hy·phen·ate ['hī-fə-,nāt] -vt, n

  1. to connect (as two words) or divide (as a word at the end of a line of print) with a hyphen

hyphenate -n

  1. a person who performs more than one function (as a producer-director in filmmaking)

hyphenated -adj

  1. of, relating to, or being an individual or unit of mixed or diverse background or composition
    • hyphenated Americans

hypn- -comb form

  1. sleep
    • hypno pompic
  2. hypnotism
    • hypno therapy

hyp·na·go·gic [,hip-nə-'gä-jik, -'gō-] -adj

  1. of, relating to, or occurring in the period of drowsiness immediately preceding sleep
    • hypnagogic hallucinations

hyp·noid ['hip-,nȯid] -adj

  1. of or relating to sleep or hypnosis

hyp·no·pom·pic [,hip-nə-'päm-pik] -adj

  1. associated with the semiconsciousness preceding waking
    • hypnopompic illusions

Hyp·nos ['hip-nəs, -,nōs] -n

  1. the Greek god of sleep

hyp·no·sis [hip-'nō-səs] -n

  1. a trancelike state that resembles sleep but is induced by a person whose suggestions are readily accepted by the subject
  2. any of various conditions that resemble sleep
  3. hypnotism

hyp·no·ther·a·py [,hip-nō-'ther-ə-pē] -n

  1. treatment by hypnotism
  2. psychotherapy that facilitates suggestion, reeducation, or analysis by hypnosis

hyp·not·ic [hip-'nä-tik] -adj, adv

  1. tending to produce sleep : soporific
  2. of or relating to hypnosis or hypnotism
  3. readily holding the attention
    • a hypnotic personality
    • a simple hypnotic beat

hypnotic -n

  1. a sleep-inducing agent : soporific
  2. one that is or can be hypnotized

hyp·no·tism ['hip-nə-,ti-zəm] -n

  1. the study or act of inducing hypnosis
  2. hypnosis

hyp·no·tize [-,tīz] -vt, n, adj

  1. to induce hypnosis in
  2. to dazzle or overcome by or as if by suggestion
    • a voice that hypnotize s its hearers
    • drivers hypnotized by speed

hy·po ['hī-(,)pō] -n

  1. hypochondria

hypo -n

  1. sodium thiosulfate
  2. a solution of sodium thiosulfate
  3. hypodermic syringe
  4. hypodermic injection
  5. stimulus
  6. stimulate
    • do everything possible to hypo the economy -- Clem Morgello

hypo- -prefix

  1. under : beneath : down
    • hypo blast
    • hypo dermic
  2. less than normal or normally
    • hyp esthesia
    • hypo tension
  3. in a lower state of oxidation : in a low and usu. the lowest position in a series of compounds
    • hypo chlorous acid
    • hypo xanthine

hy·po·al·ler·gen·ic [,hī-pō-,a-lər-'je-nik] -adj

  1. having little likelihood of causing an allergic response
    • hypoallergenic cosmetics
    • hypoallergenic foods

hy·po·blast ['hī-pə-,blast] -n

  1. the endoderm of an embryo

hy·po·cal·ce·mia [,hī-pō-,kal-'sē-mē-ə] -n, adj

  1. a deficiency of calcium in the blood

hy·po·caust ['hī-pə-,kȯst] -n

  1. an ancient Roman central heating system with underground furnace and tile flues to distribute the heat

hy·po·cen·ter ['hī-pə-,sen-tər] -n, adj

  1. the focus of an earthquake
  2. the point on the earth's surface directly below the center of a nuclear bomb explosion

hy·po·chlo·rite [,hī-pə-'klȯr-,īt] -n

  1. a salt or ester of hypochlorous acid

hy·po·chlo·rous acid [,hī-pə-'klȯr-əs-] -n

  1. an unstable strongly oxidizing but weak acid HClO obtained in solution along with hydrochloric acid by reaction of chlorine with water and used esp. in the form of salts as an oxidizing agent, bleaching agent, disinfectant, and chlorinating agent

hy·po·chon·dria [,hī-pə-'kän-drē-ə] -n

  1. extreme depression of mind or spirits often centered on imaginary physical ailments
  2. hypochondriasis

hy·po·chon·dri·ac [-drē-,ak] -adj

  1. hypochondriacal
  2. of, relating to, or being the two regions of the abdomen lying on either side of the epigastric region and above the lumbar regions

hypochondriac -n

  1. one affected by hypochondria

hy·po·chon·dri·a·cal [-kən-'drī-ə-kəl, -,kän-] -adj, adv

  1. affected or produced by hypochondria

hy·po·chon·dri·a·sis [-'drī-ə-səs] -n

  1. morbid concern about one's health esp. when accompanied by delusions of physical disease

hy·po·chro·mic [,hī-pə-'krō-mik] -adj

  1. marked by or being red blood cells with deficient hemoglobin
    • hypochromic anemia

hy·po·co·rism [hī-'pä-kə-,ri-zəm; ,hī-pə-'kȯr-,i-] -n, adj, adv

  1. a pet name
  2. the use of pet names

hy·po·cot·yl ['hī-pə-,kä-tᵊl] -n

  1. the part of the axis of a plant embryo or seedling below the cotyledon

hy·poc·ri·sy [hi-'pä-krə-sē also hī-] -n

  1. a feigning to be what one is not or to believe what one does not
  2. the false assumption of an appearance of virtue or religion
  3. an act or instance of hypocrisy

hyp·o·crite ['hi-pə-,krit] -n, adj

  1. a person who puts on a false appearance of virtue or religion
  2. a person who acts in contradiction to his or her stated beliefs or feelings

hyp·o·crit·i·cal [,hi-pə-'kri-ti-kəl] -adj, adv

  1. characterized by hypocrisy
  2. being a hypocrite

hy·po·cy·cloid [,hī-pō-'sī-,klȯid] -n

  1. a curve traced by a point on the circumference of a circle rolling internally on the circumference of a fixed circle

hy·po·der·mal [,hī-pə-'dər-məl] -adj

  1. of or relating to a hypodermis
  2. lying beneath an outer skin or epidermis

hy·po·der·mic [-mik] -adj, adv

  1. adapted for use in or administered by injection beneath the skin
  2. of or relating to the parts beneath the skin
  3. resembling a hypodermic injection in effect : stimulating

hypodermic -n

  1. hypodermic injection
  2. hypodermic syringe

hypodermic injection -n

  1. an injection made into the subcutaneous tissues

hypodermic needle -n

  1. needle
  2. a hypodermic syringe complete with needle

hypodermic syringe -n

  1. a small syringe used with a hollow needle for injection of material into or beneath the skin

hy·po·der·mis [,hī-pə-'dər-məs] -n

  1. the tissue immediately beneath the epidermis of a plant esp. when modified to serve as a supporting and protecting layer
  2. the cellular layer that underlies and secretes the chitinous cuticle (as of an arthropod)
  3. superficial fascia

hy·po·dip·loid [,hī-pō-'di-,plȯid] -adj, n

  1. having slightly fewer than the diploid number of chromosomes

hy·po·eu·tec·toid [,hī-pō-yu̇-'tek-,tȯid] -adj

  1. containing less of the minor component than is contained in the eutectoid

hy·po·gas·tric [,hī-pə-'gas-trik] -adj

  1. of or relating to the lower median region of the abdomen

hy·po·ge·al [,hī-pə-'jē-əl] -adj

  1. growing or living below the surface of the ground
  2. remaining below the ground while the epicotyl elongates

hy·po·gene ['hī-pə-,jēn] -adj

  1. formed, crystallized, or lying at depths below the earth's surface : plutonic used of various rocks

hy·po·ge·um [,hī-pə-'jē-əm] -n

  1. the subterranean part of an ancient building
  2. an ancient underground burial chamber

hy·po·glos·sal [,hī-pə-'glä-səl] -adj

  1. of or relating to the hypoglossal nerves

hypoglossal nerve -n

  1. either of the 12th and final pair of cranial nerves which are motor nerves arising from the medulla oblongata and supplying muscles of the tongue in higher vertebrates called also hypoglossal

hy·po·gly·ce·mia [,hī-pō-glī-'sē-mē-ə] -n, adj or n

  1. abnormal decrease of sugar in the blood

hy·pog·y·nous [hī-'pä-jə-nəs] -adj, n

  1. inserted upon the receptacle or axis below the gynoecium and free from it
  2. having hypogynous floral organs

hy·po·ka·le·mia [,hī-pō-,kā-'lē-mē-ə] -n, adj

  1. a deficiency of potassium in the blood

hy·po·lim·ni·on [,hī-pō-'lim-nē-,än, -nē-ən] -n

  1. the part of a lake below the thermocline made up of water that is stagnant and of essentially uniform temperature except during the period of overturn

hy·po·mag·ne·se·mia [,hī-pə-,mag-nə-'sē-mē-ə] -n

  1. deficiency of magnesium in the blood

hy·po·ma·nia [,hī-pə-'mā-nē-ə, -nyə] -n, adj

  1. a mild mania esp. when part of bipolar disorder

hy·po·para·thy·roid·ism ['hī-pō-,pa-rə-'thī-,rȯi-,di-zəm] -n

  1. deficiency of parathyroid hormone in the body
  2. the resultant abnormal state marked by low serum calcium and a tendency to chronic tetany

hy·po·phar·ynx [-'fer-iŋ(k)s] -n

  1. an appendage or thickened fold on the floor of the mouth of many insects that resembles a tongue
  2. the laryngeal part of the pharynx extending from the hyoid bone to the lower margin of the cricoid cartilage

hy·po·phy·se·al [(,)hī-,pä-fə-'sē-əl, ,hī-pə-, -'zē-; ,hī-pə-'fi-zē-əl] -adj

  1. of or relating to the hypophysis

hy·poph·y·sec·to·mize [(,)hī-,pä-fə-'sek-tə-,mīz] -vt

  1. to remove the pituitary gland from

hy·poph·y·sec·to·my [-mē] -n

  1. surgical removal of the pituitary gland

hy·poph·y·sis [hī-'pä-fə-səs] -n

  1. pituitary gland

hy·po·pi·tu·ita·rism [,hī-pō-pə-'tü-ə-tə-,ri-zəm, -'tü-ə-,tri-, -'tyü-] -n, adj

  1. deficient production of growth hormones by the pituitary gland

hy·po·pla·sia [-'plā-zh(ē-)ə] -n, adj

  1. a condition of arrested development in which an organ or part remains below the normal size or in an immature state

hy·po·ploid ['hī-pō-,plȯid] -adj, n

  1. having a chromosome number slightly less than an exact multiple of the monoploid number

hy·po·sen·si·ti·za·tion [,hī-pō-,sen(t)-sə-tə-'zā-shən, -,sen(t)-stə-'zā-] -n, vt

  1. the state or process of being reduced in sensitivity esp. to an allergen : desensitization

hy·po·spa·di·as [,hī-pə-'spā-dē-əs] -n

  1. an abnormality of the penis in which the urethra opens on the undersurface

hy·pos·ta·sis [hī-'päs-tə-səs] -n, adj, adv

  1. something that settles at the bottom of a fluid
  2. the settling of blood in the dependent parts of an organ or body
  3. person
  4. the substance or essential nature of an individual
  5. something that is hypostatized
  6. failure of a gene to produce its usual effect when coupled with another gene that is epistatic toward it

hy·pos·ta·tize [hī-'päs-tə-,tīz] -vt, n

  1. to attribute real identity to (a concept)

hy·po·stome ['hī-pə-,stōm] -n

  1. : any of several structures associated with the mouth: as
  2. the manubrium of a hydrozoan
  3. a rodlike organ that arises at the base of the beak in various mites and ticks

hy·po·style ['hī-pə-,stī(-ə)l] -adj, n

  1. having the roof resting on rows of columns

hy·po·tac·tic [,hī-pə-'tak-tik] -adj

  1. of or relating to hypotaxis

hy·po·tax·is [-'tak-səs] -n

  1. syntactic subordination (as by a conjunction)

hy·po·ten·sion [,hī-pō-'ten(t)-shən] -n

  1. abnormally low blood pressure

hy·po·ten·sive [,hī-pō-'ten(t)-siv] -adj

  1. characterized by or due to hypotension
  2. causing low blood pressure or a lowering of blood pressure
    • hypotensive drugs

hypotensive -n

  1. a person with hypotension

hy·pot·e·nuse [hī-'pä-tə-,nüs, -,nyüz] -n

  1. the side of a right-angled triangle that is opposite the right angle
  2. the length of a hypotenuse

hy·po·tha·lam·ic [,hī-pō-thə-'la-mik] -adj

  1. of or relating to the hypothalamus
    • hypothalamic neurons

hy·po·thal·a·mus [-'tha-lə-məs] -n

  1. a basal part of the diencephalon that lies beneath the thalamus on each side, forms the floor of the third ventricle, and includes vital autonomic regulatory centers

hy·poth·e·cate [hi-'pä-thə-,kāt, hī-] -vt, n

  1. to pledge as security without delivery of title or possession
  2. hypothesize

hy·po·ther·mal [,hī-pō-'thər-məl] -adj

  1. of or relating to a hydrothermal metalliferous ore vein deposited at high temperature

hy·po·ther·mia [-'thər-mē-ə] -n, adj

  1. subnormal temperature of the body

hy·poth·e·sis [hī-'pä-thə-səs] -n

  1. an assumption or concession made for the sake of argument
  2. an interpretation of a practical situation or condition taken as the ground for action
  3. a tentative assumption made in order to draw out and test its logical or empirical consequences
  4. the antecedent clause of a conditional statement

hy·poth·e·size [-,sīz] -vb

  1. to make a hypothesis
  2. to adopt as a hypothesis

hy·po·thet·i·cal [,hī-pə-'the-ti-kəl] -adj, n, adv

  1. being or involving a hypothesis : conjectural
    • hypothetical arguments
    • a hypothetical situation

hy·po·thet·i·code·duc·tive [,hī-pə-'the-ti-,kō-di-'dək-tiv] -adj

  1. relating to, being, or making use of the method of proposing hypotheses and testing their acceptability or falsity by determining whether their logical consequences are consistent with observed data

hy·po·thy·roid [,hī-pō-'thī-,rȯid] -adj

  1. of, relating to, or affected with hypothyroidism

hy·po·thy·roid·ism [-,rȯi-,di-zəm] -n

  1. deficient activity of the thyroid gland
  2. a resultant bodily condition characterized by lowered metabolic rate and general loss of vigor

hy·po·to·nia [,hī-pə-'tō-nē-ə, -pō-] -n

  1. the state of having hypotonic muscle tone

hy·po·ton·ic [,hī-pə-'tä-nik, -pō-] -adj, n

  1. having deficient tone or tension
    • hypotonic children
  2. having a lower osmotic pressure than a surrounding medium or a fluid under comparison
    • hypotonic organisms

hy·po·xan·thine [,hī-pō-'zan-,thēn] -n

  1. a purine base C 5H 4N 4O found in plant and animal tissues that yields xanthine on oxidation

hyp·ox·emia [,hi-,päk-'sē-mē-ə, ,hī-] -n, adj

  1. deficient oxygenation of the blood

hyp·ox·ia [hi-'päk-sē-ə, hī-] -n, adj

  1. a deficiency of oxygen reaching the tissues of the body

hyp·som·e·ter [hip-'sä-mə-tər] -n

  1. any of various instruments for determining the height of trees by triangulation

hyp·so·met·ric [,hip-sə-'me-trik] -adj

  1. of, relating to, or indicating elevation (as on a map)
    • hypsometric curve

hy·rax ['hī-,raks] -n

  1. any of a family (Procaviidae) of small ungulate mammals of Africa and the Middle East characterized by thickset body with short legs and ears and rudimentary tail, feet with soft pads and broad nails, and teeth of which the molars resemble those of the rhinoceros and the incisors those of rodents called also coney dassie

hy·son ['hī-sᵊn] -n

  1. a Chinese green tea made from thinly rolled and twisted leaves

hys·sop ['hi-səp] -n

  1. a plant used in purificatory sprinkling rites by the ancient Hebrews
  2. a European mint ( Hyssopus officinalis) that has highly aromatic and pungent leaves and is sometimes used as a potherb

hyster- -comb form

  1. womb
    • hyster ectomy

hys·ter·ec·to·my [,his-tə-'rek-tə-mē] -n, adj

  1. surgical removal of the uterus

hys·ter·e·sis [,his-tə-'rē-səs] -n, adj

  1. a retardation of an effect when the forces acting upon a body are changed (as if from viscosity or internal friction)
  2. a lagging in the values of resulting magnetization in a magnetic material (as iron) due to a changing magnetizing force

hys·te·ria [his-'ter-ē-ə, -'tir-] -n, adj, adv

  1. a psychoneurosis marked by emotional excitability and disturbances of the psychic, sensory, vasomotor, and visceral functions
  2. behavior exhibiting overwhelming or unmanageable fear or emotional excess
    • political hysteria

hys·ter·ics [-'ter-iks] -n pl but sing or pl in constr

  1. a fit of uncontrollable laughter or crying

hys·ter·oid ['his-tə-,rȯid] -adj

  1. resembling or tending toward hysteria

hys·ter·on prot·er·on [,his-tə-,rän-'prä-tə-,rän, -tə-rən-'prä-tə-rən, -'prȯ-] -n

  1. a figure of speech consisting of the reversal of a natural or rational order (as in then came the thunder and the lightning)

hys·ter·o·sal·pin·go·gram [,his-tə-rō-,sal-'piŋ-gə-,gram] -n

  1. a radiograph made by hysterosalpingography

hys·ter·o·sal·pin·gog·ra·phy [,his-tə-rō-,sal-piŋ-'gäg-rə-fē] -n

  1. examination of the uterus and fallopian tubes by radiography after injection of an opaque medium

hys·ter·o·scope ['his-tə-rō-,skōp] -n

  1. an endoscope used for hysteroscopy

hys·ter·os·co·py [,his-tə-'räs-kə-pē] -n, adj

  1. visual examination of the cervix and interior of the uterus with an endoscope

hys·ter·ot·o·my [,his-tə-'rä-tə-mē] -n

  1. surgical incision of the uterus
  2. cesarean section