er ['ə, 'ä, usu with prolonged vowel, ÷'ər] -interj

  1. used to express hesitation

Er -symbol

  1. erbium

ER -abbr

  1. earned run
  2. emergency room

era ['er-ə, 'e-rə, 'ir-ə] -n

  1. a fixed point in time from which a series of years is reckoned
  2. a memorable or important date or event
  3. one that begins a new period in the history of a person or thing
  4. a system of chronological notation computed from a given date as basis
  5. a period identified by some prominent figure or characteristic feature
    • the era of the horse and buggy
  6. a stage in development (as of a person or thing)
  7. a large division of geologic time usu. shorter than an eon
    • Paleozoic era

ERA -abbr

  1. earned run average
  2. Equal Rights Amendment

erad·i·cate [i-'ra-də-,kāt] -vt, adj, n

  1. to pull up by the roots
  2. to do away with as completely as if by pulling up by the roots
    • programs to eradicate illiteracy

erase [i-'rās, Brit -'rāz] -vb, n, adj

  1. to rub or scrape out (as written, painted, or engraved letters)
    • erase an error
  2. to remove written or drawn marks from
    • erase a blackboard
  3. to remove (recorded matter) from a magnetic medium
  4. to remove recorded matter from
    • erase a videotape
  5. to delete from a computer storage device
    • erase a file
  6. to remove from existence or memory as if by erasing
  7. to nullify the effect or force of
  8. to yield to erasure

eras·er [i-'rā-sər] -n

  1. one that erases
  2. a device (as a piece of rubber, or a felt pad) used to erase marks (as of ink or chalk)

Eras·tian [i-'ras-tē-ən, -'ras-chən] -adj, n

  1. of, characterized by, or advocating the doctrine of state supremacy in ecclesiastical affairs

era·sure [i-'rā-shər also -zhər] -n

  1. an act or instance of erasing

Er·a·to ['er-ə-,tō] -n

  1. the Greek Muse of lyric and love poetry

er·bi·um ['ər-bē-əm] -n

  1. a metallic element of the rare-earth group

ere ['er] -prep

  1. before
    • contrived ere the beginning of the world -- Norman Douglas
  2. before

Er·e·bus ['er-ə-bəs] -n

  1. a personification of darkness in Greek mythology
  2. a place of darkness in the underworld on the way to Hades

erect [i-'rekt] -adj, adv, n

  1. vertical in position
  2. not spread out or decumbent
    • an erect plant stem
    • columns still erect in the ruins
  3. standing up or out from the body
    • erect hairs
  4. characterized by firm or rigid straightness in bodily posture
    • an erect bearing
  5. directed upward
  6. alert, watchful
  7. being in a state of physiological erection
  8. to put up by the fitting together of materials or parts : build
  9. to fix in an upright position
  10. to cause to stand up or stand out
  11. to direct upward
  12. to change (an image) from an inverted to a normal position
  13. to elevate in status
  14. set up, establish
  15. encourage, embolden
  16. to draw or construct (as a perpendicular or figure) upon a given base

erec·tile [i-'rek-tᵊl, -,tī(-ə)l] -adj, n

  1. of, relating to, or capable of undergoing physiological erection
    • erectile tissue
    • erectile dysfunction
  2. capable of being raised to an upright position
    • the erectile quills of a porcupine

erec·tion [i-'rek-shən] -n

  1. the state marked by firm turgid form and erect position of a previously flaccid bodily part containing cavernous tissue when that tissue becomes dilated with blood
  2. an occurrence of such a state in the penis or clitoris
  3. the act or process of erecting something : construction
  4. something erected

erec·tor [i-'rek-tər] -n

  1. one that erects
  2. a muscle that raises or keeps a part erect

Erector -trademark

  1. used for a metal toy construction set

ere·long [er-'lȯŋ] -adv

  1. before long, soon

er·e·mite ['er-ə-,mīt] -n, adj

  1. hermit
  2. a religious recluse

er·em·urus [,er-ə-'myu̇r-əs] -n

  1. any of a genus ( Eremurus) of perennial Asian herbs of the lily family that produce tall racemes of showy blooms called also foxtail lily

ere·now [er-'nau̇] -adv

  1. heretofore

erep·sin [i-'rep-sən] -n

  1. a mixture of exopeptidases obtained esp. from the intestinal juice

er·e·thism ['er-ə-,thi-zəm] -n

  1. abnormal irritability or responsiveness to stimulation

ere·while [er-'(h)wī(-ə)l] -adv

  1. a while before : formerly

erg ['ərg] -n

  1. a centimeter-gram-second unit of work equal to the work done by a force of one dyne acting through a distance of one centimeter and equivalent to 10 7joule

erg- -comb form

  1. work
    • ergo meter

er·gas·tic [(,)ər-'gas-tik] -adj

  1. constituting the nonliving by-products of protoplasmic activity
    • ergastic substances

er·gas·to·plasm [-tə-,pla-zəm] -n, adj

  1. ribosome-studded endoplasmic reticulum

er·ga·tive ['ər-gə-tiv] -adj

  1. of, relating to, or being a language (as Inuit or Georgian) in which the objects of transitive verbs and subjects of intransitive verbs are typically marked by the same linguistic forms
  2. being an inflectional morpheme that typically marks the subject of a transitive verb in an ergative language

er·go ['er-(,)gō, 'ər-] -adv

  1. therefore, hence

ergo- -comb form

  1. ergot
    • ergo sterol

er·go·dic [(,)ər-'gä-dik, -'gō-] -adj, n

  1. of or relating to a process in which every sequence or sizable sample is equally representative of the whole (as in regard to a statistical parameter)
  2. involving or relating to the probability that any state will recur
  3. having zero probability that any state will never recur

er·go·gen·ic [,ər-gə-'je-nik] -adj

  1. enhancing physical performance
    • athletic use of caffeine and other ergogenic aids

er·go·graph ['ər-gə-,graf] -n

  1. an apparatus for measuring the work capacity of a muscle

er·gom·e·ter [(,)ər-'gä-mə-tər] -n, adj

  1. an apparatus for measuring the work performed (as by a person exercising)
  2. an exercise machine equipped with an ergometer

er·go·nom·ics [,ər-gə-'nä-miks] -n pl but sing or pl in constr, adj, adv, n

  1. an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely called also biotechnology human engineering human factors
  2. the design characteristics of an object resulting esp. from the application of the science of ergonomics

er·go·no·vine [,ər-gə-'nō-,vēn] -n

  1. an alkaloid C 19H 23N 3O 2derived from ergot and used esp. in the form of its maleate as an oxytocic

er·gos·ter·ol [(,)ər-'gäs-tə-,rȯl, -,rōl] -n

  1. a crystalline steroid alcohol C 28H 44O that occurs esp. in yeast, molds, and ergot and is converted by ultraviolet irradiation ultimately into vitamin D 2

er·got ['ər-gət, -,gät] -n, adj

  1. the black or dark purple sclerotium of fungi (genus Claviceps) that occurs as a club-shaped body replacing the seed of a grass (as rye)
  2. a fungus bearing ergots
  3. a disease of rye and other cereals caused by an ergot fungus
  4. the dried sclerotia of an ergot fungus grown on rye and containing several alkaloids (as ergonovine and ergotamine)
  5. any of such alkaloids used medicinally for their contractile effect on smooth muscle (as of the uterus and or blood vessels)

er·got·a·mine [(,)ər-'gä-tə-,mēn] -n

  1. an alkaloid C 33H 35N 5O 5derived from ergot that is used chiefly in the form of its tartrate esp. in treating migraine

er·got·ism ['ər-gə-,ti-zəm] -n

  1. a toxic condition produced by eating grain, grain products (as rye bread), or grasses infected with ergot fungus or by chronic excessive use of an ergot drug

er·got·ized [-,tīzd] -adj

  1. infected with ergot
    • ergotized grain
  2. poisoned by ergot
    • ergotized cattle

er·i·ca ['er-i-kə] -n

  1. any of a large genus ( Erica) of evergreen chiefly African plants of the heath family ranging from low shrubs to small trees

er·i·ca·ceous [,er-ə-'kā-shəs] -adj

  1. of, relating to, or being a heath or the heath family

er·i·coid ['er-ə-,kȯid] -adj

  1. resembling heath
    • ericoid foliage

Erie ['ir-ē] -n

  1. a member of an American Indian people living south of Lake Erie in the 17th century
  2. the extinct and prob. Iroquoian language of the Erie people

erig·er·on [ə-'ri-jə-,rän] -n

  1. any of a widely distributed genus ( Erigeron) of composite herbs with flower heads that resemble asters but have fewer and narrower involucral bracts

Eri·nys [i-'ri-nəs, -'rī-] -n

  1. fury

er·i·o·phy·id [,er-ē-'ä-fē-əd, -ē-ə-'fī-əd] -n, adj

  1. any of a large family (Eriophyidae) of minute plant-feeding wormlike mites that have two pairs of legs and include gall mites and rust mites

Eris ['er-is] -n

  1. a dwarf planet with a mean distance from the sun of 67 astronomical units (6.2 billion miles) and a diameter of 1500 miles (2400 kilometers)

ERISA -abbr

  1. Employee Retirement Income Security Act

eris·tic [i-'ris-tik, e-] -adj, adv

  1. characterized by disputatious and often subtle and specious reasoning

eristic -n

  1. a person devoted to logical disputation
  2. the art or practice of disputation and polemics

Er·len·mey·er flask ['ər-lən-,mī(-ə)r-, 'er-lən-] -n

  1. a flat-bottomed conical laboratory flask

er·mine ['ər-mən] -n

  1. any of several weasels whose coats become white in winter usu. with black on the tip of the tail
  2. a short-tailed weasel ( Mustela erminea) of the forests and tundra of Eurasia and No. America
  3. the white fur of the ermine
  4. a rank or office whose ceremonial or official robe is ornamented with ermine

er·mined [-mənd] -adj

  1. clothed or adorned with ermine

erne ['ərn, 'ern] -n

  1. eagle
  2. a long-winged sea eagle ( Haliaetus albicilla) with a short white wedge-shaped tail

erode [i-'rōd] -vb, n, adj

  1. : to diminish or destroy by degrees:
  2. to eat into or away by slow destruction of substance (as by acid, infection, or cancer)
  3. to wear away by the action of water, wind, or glacial ice
    • flooding eroded the hillside
  4. to cause to deteriorate or disappear as if by eating or wearing away
    • inflation eroding buying power
  5. to produce or form by eroding
    • glaciers erode U-shaped valleys
  6. to undergo erosion
    • where the land has eroded away

erog·e·nous [i-'rä-jə-nəs] -adj

  1. producing sexual excitement or libidinal gratification when stimulated : sexually sensitive
  2. of, relating to, or arousing sexual feelings

Eros ['er-,äs, 'ir-] -n

  1. the Greek god of erotic love
  2. the sum of life-preserving instincts that are manifested as impulses to gratify basic needs, as sublimated impulses, and as impulses to protect and preserve the body and mind
  3. love conceived by Plato as a fundamental creative impulse having a sensual element
  4. erotic love or desire

erose [i-'rōs] -adj

  1. irregular, uneven
  2. having the margin irregularly notched
    • an erose leaf

ero·sion [i-'rō-zhən] -n, adj, adv

  1. the action or process of eroding
  2. the state of being eroded
  3. an instance or product of erosion

ero·sive [i-'rō-siv, -ziv] -adj, n

  1. tending to erode or to induce or permit erosion
  2. caused or marked by erosion
    • erosive arthritis

erot·ic [i-'rä-tik] -adj, n, adv

  1. of, devoted to, or tending to arouse sexual love or desire
    • erotic art
  2. strongly marked or affected by sexual desire

erot·i·ca [i-'rä-ti-kə] -n pl but sing or pl in constr

  1. literary or artistic works having an erotic theme or quality
  2. depictions of things erotic

erot·i·cism [i-'rä-tə-,si-zəm] -n

  1. an erotic theme or quality
  2. a state of sexual arousal
  3. insistent sexual impulse or desire

erot·i·cize [-,sīz] -vt, n

  1. to make erotic
    • eroticize the male image

er·o·tism ['er-ə-,ti-zəm] -n

  1. eroticism

er·o·tize ['er-ə-,tīz] -vt, n

  1. to invest with erotic significance or sexual feeling

eroto- -comb form

  1. sexual desire
    • eroto genic

ero·to·gen·ic [i-,rō-tə-'je-nik, -,rä-] -adj

  1. erogenous

ero·to·ma·nia [i-,rō-tə-'mā-nē-ə, -,rä-] -n

  1. excessive sexual desire
  2. a psychological disorder marked by the delusional belief that one is the object of another person's love or sexual desire

err ['er, 'ər] -vi

  1. stray
  2. to make a mistake
    • err ed in his calculations
    • err ed on the side of caution
  3. to violate an accepted standard of conduct

er·ran·cy ['er-ən(t)-sē, 'e-rən(t)-] -n

  1. the state or an instance of erring

er·rand ['er-ənd, 'e-rənd] -n

  1. an oral message entrusted to a person
  2. embassy, mission
  3. a short trip taken to attend to some business often for another
    • was on an errand for his mother
  4. the object or purpose of such a trip

er·rant ['er-ənt, 'e-rənt] -adj, n, adv

  1. traveling or given to traveling
    • an errant knight
  2. straying outside the proper path or bounds
    • an errant calf
  3. moving about aimlessly or irregularly
    • an errant breeze
  4. behaving wrongly
    • an errant child
  5. fallible

er·rant·ry ['er-ən-trē, 'e-rən-] -n

  1. the quality, condition, or fact of wandering
  2. a roving in search of chivalrous adventure

er·ra·ta [e-'rä-tə, -'rā-, -'ra-] -n

  1. a list of corrigenda
  2. a page bearing such a list

er·rat·ic [i-'ra-tik] -adj, adv, n

  1. having no fixed course : wandering
    • an erratic comet
  2. nomadic
  3. transported from an original resting place esp. by a glacier
    • an erratic boulder
  4. characterized by lack of consistency, regularity, or uniformity
    • erratic dieting
    • keeps erratic hours
  5. deviating from what is ordinary or standard : eccentric
    • an erratic genius

erratic -n

  1. one that is erratic
  2. an erratic boulder or block of rock

er·ra·tum [e-'rä-təm, -'rā-, -'ra-] -n

  1. error
  2. corrigendum

er·ro·ne·ous [i-'rō-nē-əs, e-] -adj, adv, n

  1. containing or characterized by error : mistaken
    • erroneous assumptions
    • gave an erroneous impression
  2. wandering

er·ror ['er-ər, 'e-rər] -n, adj

  1. an act or condition of ignorant or imprudent deviation from a code of behavior
  2. an act involving an unintentional deviation from truth or accuracy
    • made an error in adding up the bill
  3. : an act that through ignorance, deficiency, or accident departs from or fails to achieve what should be done
    • an error in judgment
    : as
  4. a defensive misplay other than a wild pitch or passed ball made by a baseball player when normal play would have resulted in an out or prevented an advance by a base runner
  5. the failure of a player (as in tennis) to make a successful return of a ball during play
  6. a mistake in the proceedings of a court of record in matters of law or of fact
  7. the quality or state of erring
    • the map is in error
  8. illusion about the nature of reality that is the cause of human suffering : the contradiction of truth
  9. an instance of false belief
  10. something produced by mistake
    • a typographical error
  11. a postage stamp exhibiting a consistent flaw (as a wrong color) in its manufacture
  12. the difference between an observed or calculated value and a true value
  13. variation in measurements, calculations, or observations of a quantity due to mistakes or to uncontrollable factors
  14. the amount of deviation from a standard or specification
  15. a deficiency or imperfection in structure or function
    • an error of metabolism

error bar -n

  1. the estimated uncertainty in experimental data

er·satz ['er-,säts, -,zäts, er-'; 'ər-,sats] -adj, n

  1. being a usu. artificial and inferior substitute or imitation
    • ersatz turf
    • ersatz intellectuals

Erse ['ərs] -n, adj

  1. scottish gaelic
  2. irish gaelic

erst ['ərst] -adv

  1. erstwhile

erst·while ['ərst-,(h)wī(-ə)l] -adv

  1. in the past : formerly
    • cultures, erstwhile unknown to each other -- Robert Plank

erstwhile -adj

  1. former, previous
    • erstwhile enemies

ERT -abbr

  1. estrogen replacement therapy

eru·cic acid [i-'rü-sik-] -n

  1. a crystalline fatty acid C 22H 42O 2found in the form of glycerides esp. in rapeseed oil

eruct [i-'rəkt] -vb

  1. belch

eruc·ta·tion [i-,rək-'tā-shən, ,ē-] -n

  1. an act or instance of belching

er·u·dite ['er-ə-,dīt, 'er-yə-] -adj, adv

  1. possessing or displaying erudition : learned
    • an erudite scholar

er·u·di·tion [,er-ə-'di-shən, ,er-yə-] -n

  1. extensive knowledge acquired chiefly from books : profound, recondite, or bookish learning

erupt [i-'rəpt] -vb, adj, adv

  1. to burst from limits or restraint
  2. to emerge through the gum
  3. to force out or release suddenly and often violently something (as lava or steam) that is pent up
  4. to become active or violent esp. suddenly : break forth
    • war could erupt at any moment
    • the audience erupt ed in applause
  5. to break out with or as if with a skin eruption
  6. to force out or release usu. suddenly and violently
    • a volcano erupt ing lava and ash

erup·tion [i-'rəp-shən] -n

  1. an act, process, or instance of erupting
  2. the breaking out of a rash on the skin or mucous membrane
  3. a product of erupting (as a skin rash)

eryn·go [i-'riŋ-(,)gō] -n

  1. any of various plants (genus Eryngium) of the carrot family that have elongate spinulose-margined leaves and flowers in dense bracted heads
  2. candied root of the sea holly formerly used as an aphrodisiac

ery·sip·e·las [,er-ə-'si-p(ə-)ləs, ,ir-] -n

  1. an acute febrile disease associated with intense edematous local inflammation of the skin and subcutaneous tissues caused by a hemolytic streptococcus

er·y·the·ma [,er-ə-'thē-mə] -n, adj

  1. abnormal redness of the skin due to capillary congestion

erythema mi·grans [-'mī-grənz] -n

  1. a red spreading annular skin lesion that is an early symptom of Lyme disease and that develops at the site of the bite of a tick (as the deer tick) infected with the causative spirochete

er·y·thor·bate [,er-ə-'thȯr-,bāt] -n

  1. a salt of erythorbic acid that is used in foods as an antioxidant

er·y·thor·bic acid [-,thȯr-bik-] -n

  1. a diastereoisomer of ascorbic acid with optical activity

erythr- -comb form

  1. red
    • erythro cyte
  2. erythrocyte
    • erythr oid

er·y·thre·mia [,er-ə-'thrē-mē-ə] -n

  1. polycythemia vera

er·y·thrism ['er-ə-,thri-zəm] -n, adj

  1. a condition marked by exceptional prevalence of red pigmentation (as in hair or feathers)

er·y·thrite ['er-ə-,thrīt] -n

  1. a usu. rose-colored mineral consisting of a hydrous cobalt arsenate occurring esp. in monoclinic crystals

eryth·ro·blast [i-'rith-rə-,blast] -n, adj

  1. a polychromatic nucleated cell of red bone marrow that synthesizes hemoglobin and that is an intermediate in the initial stage of red blood cell formation
  2. a cell ancestral to red blood cells

eryth·ro·blas·to·sis [i-,rith-rə-,blas-'tō-səs] -n

  1. abnormal presence of erythroblasts in the circulating blood
  2. erythroblastosis fetalis

erythroblastosis fe·ta·lis [-fi-'ta-ləs] -n

  1. a hemolytic disease of the fetus and newborn that occurs when the system of an Rh-negative mother produces antibodies to an antigen in the blood of an Rh-positive fetus which cross the placenta and destroy fetal erythrocytes and that is characterized by an increase in circulating erythroblasts and by jaundice

eryth·ro·cyte [i-'rith-rə-,sīt] -n, adj

  1. red blood cell

ery·throid [i-'rith-,rȯid, 'er-ə-,thrȯid] -adj

  1. relating to erythrocytes or their precursors

eryth·ro·my·cin [i-,rith-rə-'mī-sᵊn] -n

  1. a broad-spectrum antibiotic C 37H 67NO 13produced by an actinomycete ( Streptomyces erythreus) and administered orally or topically

eryth·ro·poi·e·sis [i-,rith-rō-pȯi-'ē-səs] -n, adj

  1. the production of red blood cells (as from the bone marrow)

eryth·ro·poi·e·tin [-'pȯi-ə-tən] -n

  1. a glycoprotein hormone formed esp. in the kidney and stimulating red blood cell formation

eryth·ro·sin [i-'rith-rə-sən] -n

  1. any of several dyes made from fluorescein that yield reddish shades