ur- -comb form
- urine
- urinary tract
- urinary and
- urea
- tail
- original : primitive
- original version of
- prototypical : arch-
ura·cil ['yu̇r-ə-,sil, -səl] -n
- a pyrimidine base C 4H 4N 2O 2that is one of the four bases coding genetic information in the polynucleotide chain of RNA
urae·us [yu̇-'rē-əs] -n
- a representation of the sacred asp ( Naja haje) appearing in ancient Egyptian art and esp. on the headdress of rulers and serving as a symbol of sovereignty
UralAl·ta·ic [,yu̇r-əl-al-'tā-ik] -n, adj
- a postulated language family comprising the Uralic and Altaic languages
Ura·li·an [yu̇-'rā-lē-ən, -'ra-] -adj
- of or relating to the Ural mountains
- uralic
Ural·ic [yu̇-'ra-lik] -n
- a language family comprising the Finno-Ugric and Samoyed languages
Uralic -adj
- of, relating to, or constituting the Finno-Ugric and Samoyed languages
Ura·nia [yu̇-'rā-nē-ə, -nyə] -n
- the Greek Muse of astronomy
Ura·ni·an [yu̇-'rā-nē-ən, -nyən] -adj
- of or relating to the planet Uranus
ura·ni·nite [yu̇-'rā-nə-,nīt] -n
- a black octahedral mineral that consists of an oxide of uranium which usu. contains thorium, lead, and rare earth elements and is the chief ore of uranium
ura·ni·um [yu̇-'rā-nē-əm] -n
- a silvery heavy radioactive polyvalent metallic element that is found esp. in uraninite and exists naturally as a mixture of mostly nonfissionable isotopes
uranium hexa·flu·o·ride [-,hek-sə-'flȯr-,īd, -'flu̇r-] -n
- a volatile compound UF 6of uranium and fluorine that is used in one major process of enriching uranium in uranium 235
uranium 238 -n
- an isotope of uranium of mass number 238 that is the most stable uranium isotope, that constitutes over 99 percent of natural uranium, that is not fissile but can be used to produce a fissile isotope of plutonium, and that has a half-life of 4.5 billion years
uranium 235 -n
- a light isotope of uranium of mass number 235 that constitutes less than one percent of natural uranium, that when bombarded with slow neutrons undergoes rapid fission into smaller atoms with the release of neutrons and energy, and that is used in nuclear reactors and atomic bombs
ura·nog·ra·phy [,yu̇r-ə-'nä-grə-fē] -n
- the construction of celestial representations (as maps)
Ura·nus ['yu̇r-ə-nəs, yu̇-'rā-] -n
- the sky personified as a god and father of the Titans in Greek mythology
- the planet seventh in order from the sun
ura·nyl ['yu̇r-ə-,nil, yu̇-'rā-nᵊl] -n
- a divalent radical UO 2
urate ['yu̇r-,āt] -n, adj
- a salt of uric acid
ur·ban ['ər-bən] -adj
- of, relating to, characteristic of, or constituting a city
ur·bane [,ər-'bān] -adj, adv
- notably polite or polished in manner
ur·ban·i·sa·tion [,ər-bə-nə-'zā-shən] -n
(variant of urbanization)
- the quality or state of being urbanized or the process of becoming urbanized
ur·ban·ism ['ər-bə-,ni-zəm] -n
- the characteristic way of life of city dwellers
- the study of the physical needs of urban societies
- city planning
- urbanization
ur·ban·ist ['ər-bə-nist] -n, adj, adv
- a specialist in city planning
ur·ban·ite ['ər-bə-,nīt] -n
- a person who lives in a city
ur·ban·i·ty [,ər-'ba-nə-tē] -n
- the quality or state of being urbane
- urbane acts or conduct
ur·ban·i·za·tion [,ər-bə-nə-'zā-shən] -n
- the quality or state of being urbanized or the process of becoming urbanized
ur·ban·ize ['ər-bə-,nīz] -vt
- to cause to take on urban characteristics
- to impart an urban way of life to
- urbanize migrants from rural areas
urban legend -n
- an often lurid story or anecdote that is based on hearsay and widely circulated as true
- the urban legend of alligators living in the sewers
called also urban myth
ur·ban·ol·o·gy [,ər-bə-'nä-lə-jē] -n
- a study dealing with specialized problems of cities (as planning, education, sociology, and politics)
urban renewal -n
- a construction program to replace or restore substandard buildings in an urban area
urban sprawl -n
- the spreading of urban developments (as houses and shopping centers) on undeveloped land near a city
ur·ce·o·late [,ər-'sē-ə-lət, 'ər-sē-ə-,lāt] -adj
- shaped like an urn
ur·chin ['ər-chən] -n
- hedgehog
- a mischievous and often poor and raggedly clothed youngster
- sea urchin
urd ['u̇rd, 'ərd] -n
- an annual Asian legume ( Vigna mungosyn. Phaseolus mungo) widely grown in warm regions for its edible blackish seed, for green manure, or for forage
- the seed
Ur·du ['u̇r-(,)dü, 'ər-] -n
- an Indo-Aryan language that has the same colloquial basis as standard Hindi, is an official language of Pakistan, and is widely used by Muslims in urban areas of India
urea [yu̇-'rē-ə] -n
- a soluble weakly basic nitrogenous compound CO(NH 2) 2that is the chief solid component of mammalian urine and an end product of protein decomposition, is synthesized from carbon dioxide and ammonia, and is used esp. in synthesis (as of resins and plastics) and in fertilizers and animal rations
ureaformaldehyde -n
- a thermosetting synthetic resin made by condensing urea with formaldehyde
ure·ase ['yu̇r-ē-,ās, -,āz] -n
- an enzyme that catalyzes the hydrolysis of urea
ure·din·i·um [,yu̇r-ə-'di-nē-əm] -n, adj
- a usu. reddish or black mass of hyphae and spores of a rust fungus forming pustules that rupture the host's cuticle
ure·do·spore [yu̇-'rē-də-,spȯr] -n
- one of the thin-walled spores that are produced by uredinial hyphae and spread the fungus vegetatively
ure·ide ['yu̇r-ē-,īd] -n
- a cyclic or acyclic acyl derivative of urea
ure·mia [yu̇-'rē-mē-ə] -n, adj
- accumulation in the blood of constituents normally eliminated in the urine that produces a severe toxic condition and usu. occurs in severe kidney disease
- the toxic bodily condition associated with uremia
ureo·tel·ic [yu̇-,rē-ə-'te-lik, ,yu̇r-ē-ō-] -adj, n
- excreting nitrogen mostly in the form of urea
ure·ter ['yu̇r-ə-tər, yu̇-'rē-tər] -n, adj
- a duct that carries away the urine from a kidney to the bladder or cloaca
ure·thane ['yu̇r-ə-,thān] -n
- a crystalline compound C 3H 7NO 2that is the ethyl ester of carbamic acid and is used esp. as a solvent and medicinally as an antineoplastic agent
- an ester of carbamic acid other than the ethyl ester
- polyurethane
ure·thra [yu̇-'rē-thrə] -n, adj
- the canal that in most mammals carries off the urine from the bladder and in the male serves also as a passageway for semen
ure·thri·tis [,yu̇r-i-'thrī-təs] -n
- inflammation of the urethra
ure·thro·scope [yu̇-'rē-thrə-,skōp] -n
- an instrument for viewing the interior of the urethra
urge ['ərj] -vb, n
- to present, advocate, or demand earnestly or pressingly
- his conviction was upheld on a theory never urged at his...trial -- Leon Friedman
- to undertake the accomplishment of with energy, swiftness, or enthusiasm
- solicit, entreat
- to serve as a motive or reason for
- to force or impel in an indicated direction or into motion or greater speed
- the dog urged the sheep toward the gate
- stimulate, provoke
- urge not my father's anger -- Shak.
- to declare, advance, or press earnestly a statement, argument, charge, or claim
- urged for the adoption of the proposal
- the act or process of urging
- a force or impulse that urges
- a continuing impulse toward an activity or goal
urge incontinence -n
- involuntary leakage of urine from the bladder when a sudden strong need to urinate is felt
ur·gen·cy ['ər-jən(t)-sē] -n
- the quality or state of being urgent : insistence
- a force or impulse that impels or constrains : urge
ur·gent ['ər-jənt] -adj, adv
- calling for immediate attention : pressing
- conveying a sense of urgency
- urging insistently : importunate
uri·al ['u̇r-ē-əl, -,äl] -n
- an upland wild sheep ( Ovis vignei) of southern and central Asia which is reddish brown and the males of which have a beard from the neck to the chest
uric ['yu̇r-ik] -adj
- of, relating to, or found in urine
uric acid -n
- a white odorless and tasteless nearly insoluble acid C 5H 4N 4O 3that is the chief nitrogenous waste present in the urine esp. of lower vertebrates (as birds and reptiles), is present in small quantity in human urine, and occurs pathologically in renal calculi and the tophi of gout
uri·co·su·ric [,yu̇r-i-kə-'shu̇r-ik, -'su̇r-] -adj
- relating to or promoting the excretion of uric acid in the urine
uri·co·tel·ic [,yu̇r-i-kō-'te-lik] -adj, n
- excreting nitrogen mostly in the form of uric acid
- birds are typical uricotelic animals
uri·dine ['yu̇r-ə-,dēn] -n
- a ribonucleoside C 9H 12N 2O 6containing uracil that in the form of phosphate derivatives plays an important role in carbohydrate metabolism
Uri·el ['yu̇r-ē-əl] -n
- one of the four archangels named in Hebrew tradition
Urim and Thum·mim [,yu̇r-ə-mən(d)-'thə-məm, ,u̇r-; ,u̇r-ēm-ən(d)-'tu̇-mēm] -n pl
- sacred lots used in early times by the Hebrews
urin- -comb form
- ur-
uri·nal ['yər-ə-nᵊl, 'yu̇r-, Brit also yu̇-'rī-nᵊl] -n
- a vessel for receiving urine
- a building or enclosure with facilities for urinating
- a fixture used for urinating
uri·nal·y·sis [,yər-ə-'na-lə-səs, ,yu̇r-] -n
- chemical analysis of urine
uri·nary ['yər-ə-,ner-ē, 'yu̇r-] -adj
- relating to, occurring in, affecting, or constituting the organs concerned with the formation and discharge of urine
- of, relating to, or for urine
- excreted as or in urine
urinary bladder -n
- a membranous sac in many vertebrates that serves for the temporary retention of urine and discharges by the urethra
uri·nate ['yər-ə-,nāt, 'yu̇r-] -vi, n
- to discharge urine : micturate
urine ['yər-ən, 'yu̇r-] -n, adj
- waste material that is secreted by the kidney in vertebrates, is rich in end products of protein metabolism together with salts and pigments, and forms a clear amber and usu. slightly acid fluid in mammals but is semisolid in birds and reptiles
uri·no·gen·i·tal [,yu̇r-ə-nō-'je-nə-tᵊl] -adj
- urogenital
uri·nom·e·ter [,yu̇r-ə-'nä-mə-tər] -n
- a small hydrometer for determining the specific gravity of urine
URL [,yü-(,)är-'el, 'ər(-ə)l] -n
- the address of a resource (as a document or Web site) on the Internet that consists of a communications protocol followed by the name or address of a computer on the network and that often includes additional locating information (as directory and file names)
- our site's URL is http://www.Merriam-Webster.com
called also uniform resource locator universal resource locator
urn ['ərn] -n
- a vessel that is typically an ornamental vase on a pedestal and that is used for various purposes (as preserving the ashes of the dead after cremation)
- a closed vessel usu. with a spigot for serving a hot beverage
uro·ca·nic acid [,yu̇r-ə-'kā-nik-, -'ka-] -n
- a crystalline acid C 6H 6N 2O 2that is normally present in human skin
uro·chor·date [,yu̇r-ə-'kȯr-dət, -,dāt] -n, adj
- tunicate
uro·chrome ['yu̇r-ə-,krōm] -n
- a yellow pigment to which the color of normal urine is principally due
uro·dele ['yu̇r-ə-,dēl] -n, adj
- any of an order (Caudata syn. Urodela) of amphibians (as newts and salamanders) that have a tail throughout life
uro·gen·i·tal [,yu̇r-ō-'je-nə-tᵊl] -adj
- of, relating to, or being the organs or functions of excretion and reproduction
uro·gy·ne·col·o·gy [,yu̇r-ō-,gī-nə-'kä-lə-jē, -,ji-] -n
- a branch of medicine concerned with urological problems affecting women
uro·ki·nase [,yu̇r-ō-'kī-,nās, -,nāz] -n
- an enzyme that is produced by the kidney and found in urine, that activates plasminogen, and that is used therapeutically to dissolve blood clots (as in the heart)
uro·lith ['yu̇r-ə-,lith] -n
- a calculus in the urinary tract
uro·lith·ia·sis [,yu̇r-ə-li-'thī-ə-səs] -n
- a condition that is marked by the formation or presence of calculi in the urinary tract
uro·logi·cal [,yu̇r-ə-'lä-ji-kəl] -adj
- of or relating to the urinary tract or to urology
urol·o·gist [yu̇-'rä-lə-jist] -n
- a physician who specializes in the urinary or urogenital tract
uron·ic acid [yu̇-'rä-nik-] -n
- any of a class of acidic compounds of the general formula HOOC(CHOH) n CHO that contain both carboxylic and aldehydic groups, are oxidation products of sugars, and occur combined in many polysaccharides and in urine
uro·pod ['yu̇r-ə-,päd] -n
- either of the flattened lateral appendages of the last abdominal segment of a crustacean
- an abdominal appendage of a crustacean
uro·py·gi·al gland [,yu̇r-ə-'pī-jē-əl-] -n
- a large gland that occurs in most birds, opens dorsally at the base of the tail feathers, and usu. secretes an oily fluid which the bird uses in preening its feathers called also oil gland
uro·py·gi·um [,yu̇r-ə-'pī-jē-əm] -n
- the fleshy and bony prominence at the posterior extremity of a bird's body that supports the tail feathers
uro·style ['yu̇r-ə-,stī(-ə)l] -n
- a long unsegmented bone that represents a number of fused vertebrae and forms the posterior part of the vertebral column of frogs and toads
Ur·sa Ma·jor [,ər-sə-'mā-jər] -n
- a constellation that is the most conspicuous of the northern constellations, is situated near the north pole of the heavens, and contains the stars forming the Big Dipper two of which are in a line indicating the direction of the North Star called also Great Bear
Ursa Mi·nor [-'mī-nər] -n
- a constellation that includes the north pole of the heavens and the stars which form the Little Dipper with the North Star at the tip of the handle called also Little Bear
ur·sine ['ər-,sīn] -adj
- of or relating to a bear or the bear family (Ursidae)
- suggesting or characteristic of a bear
Ur·su·line ['ər-sə-lən, -,līn, -,lēn] -n
- a member of any of several Roman Catholic teaching orders of nuns
- a member of a teaching order founded by St. Angela Merici in Brescia, Italy, in 1535
ur·text ['u̇r-,tekst] -n
- the original text (as of a musical score)
ur·ti·car·ia [,ər-tə-'ker-ē-ə] -n, adj
- hives
ur·ti·cate ['ər-tə-,kāt] -vi, n
- to produce wheals or itching
- to induce hives
urus ['yu̇r-əs] -n
- aurochs
uru·shi·ol [yu̇-'rü-shē-,ȯl, u̇-', -,ōl] -n
- a mixture of catechol derivatives with saturated or unsaturated side chains of 15 or 17 carbon atoms that is an oily toxic irritant principle present in poison ivy and some related plants (genus Rhus) and in lacquers derived from such plants