equerry (n.) Look up equerry at Dictionary.com
1590s, short for groom of the equirrie, from esquiry "stables" (1550s), from Middle French escuerie (Modern French écurie), perhaps from Medieval Latin scuria "stable," from Old High German scura "barn;" or from Old French escuier "groom," from Vulgar Latin scutarius "shield-bearer." In either case, spelling influenced by Latin equus "horse," which is unrelated.
equestrian (adj.) Look up equestrian at Dictionary.com
1650s, formed in English from Latin equester (genitive equestris) "of a horseman," from eques "horseman, knight," from equus "horse" (see equine). As a noun, "one who rides on horseback," from 1791. The pseudo-French fem. equestrienne is attested from 1848.
equi- Look up equi- at Dictionary.com
word-forming element meaning "equal," from Latin aequi-, comb. form of aequus "equal, even" (see equal (adj.)).
equiangular (adj.) Look up equiangular at Dictionary.com
1650s; see equi- + angular.
equidistant (adj.) Look up equidistant at Dictionary.com
1560s, from French équidistant (14c.), from Late Latin aequidistantem (nominative aequidistans), from aequi- (see equal) + distantem (see distant). In reference to a type of map projection, from 1866.
equilateral (adj.) Look up equilateral at Dictionary.com
1560s, from Late Latin aequilateralis, from aequi- (see equal (adj.)) + lateralis (see lateral).
equilibrium (n.) Look up equilibrium at Dictionary.com
c.1600, from Latin aequilibrium, from aequus "equal" (see equal (adj.)) + libra "a balance, scale, plummet" (see Libra).
equine (adj.) Look up equine at Dictionary.com
1765, from Latin equinus, from equus "horse," from PIE root *ekwo- "horse" (cognates: Greek hippos, Old Irish ech, Old English eoh, Gothic aihwa-, Sanskrit açva-, Avestan aspa-, Old Church Slavonic ehu-, all meaning "horse").
equinox (n.) Look up equinox at Dictionary.com
late 14c., from Old French equinoce (12c.) or directly from Medieval Latin equinoxium "equality of night (and day)," from Latin aequinoctium "the equinoxes," from aequus "equal" (see equal (adj.)) + nox (genitive noctis) "night" (see night). The Old English translation was efnniht. Related: Equinoctial.
equip (v.) Look up equip at Dictionary.com
1520s, from Middle French équiper "to fit out," from Old French esquiper "fit out a ship" (12c.), probably from Old Norse skipa "fit out a ship," from skip "ship" (see ship (n.)). Related: Equipped; equipping. Spanish and Portuguese esquipar are from French.
equipage (n.) Look up equipage at Dictionary.com
1570s, from French équipage (15c.), from équiper (see equip). Now largely replaced by equipment.
equiparation (n.) Look up equiparation at Dictionary.com
from Latin aequiparationem (nominative aequiparatio) "an equalizing, comparison," from aequiparare "put on equality, compare," from aequipar "equal, alike," from aequus "equal, even" (see equal (adj.)) + par (see par (n.)). Related: Equiparate.
equipment (n.) Look up equipment at Dictionary.com
1717, "things equipped;" 1748, "action of equipping;" from equip + -ment, or from French équipement. Superseding earlier equipage.
equipoise (n.) Look up equipoise at Dictionary.com
1650s, a contraction of the phrase equal poise (1550s); see equal (adj.) + poise (n.).
equitable (adj.) Look up equitable at Dictionary.com
1640s, from French équitable (16c.), from équité (see equity). Related: Equitably.
equity (n.) Look up equity at Dictionary.com
early 14c., from Old French equite (13c.), from Latin aequitatem (nominative aequitas) "equality, conformity, symmetry, fairness," from aequus "even, just, equal" (see equal (adj.)). As the name of a system of law, 1590s, from Roman naturalis aequitas, the general principles of justice which corrected or supplemented the legal codes.
equivalence (n.) Look up equivalence at Dictionary.com
1540s, from French équivalence, from Medieval Latin aequivalentia, from aequivalentem (see equivalent). Related: Equivalency (1530s).
equivalent (adj.) Look up equivalent at Dictionary.com
early 15c., from Middle French equivalent and directly from Late Latin aequivalentem (nominative aequivalens) "equivalent," present participle of aequivalere "be equivalent," from Latin aequus "equal" (see equal (adj.)) + valere "be well, be worth" (see valiant). As a noun from c.1500.
equivocal (adj.) Look up equivocal at Dictionary.com
c.1600, from Late Latin aequivocus "of equal voice, of equal significance, ambiguous" (see equivocation) + -al (1). Earlier in same sense was equivoque (late 14c.). Related: Equivocally (1570s).
equivocate (v.) Look up equivocate at Dictionary.com
early 15c., equivocaten, from Medieval Latin equivocatus, past participle of equivocare "to call by the same name," from Late Latin aequivocus (see equivocation). Related: Equivocated; equivocating.
equivocation (n.) Look up equivocation at Dictionary.com
late 14c., "the fallacy of using a word in different senses at different stages of the reasoning" (a loan-translation of Greek homonymia, literally "having the same name"), from Old French equivocation, from Late Latin aequivocationem (nominative aequivocatio), from aequivocus "of identical sound," past participle of aequivocare, from aequus "equal" (see equal (adj.)) + vocare "to call" (see voice (n.)).
equivocator (n.) Look up equivocator at Dictionary.com
1590s, from Late Latin aequivocator, agent noun from aequivocare (see equivocation).
er Look up er at Dictionary.com
as a sound of hesitation or uncertainty, attested from mid-19c.
ER Look up ER at Dictionary.com
abbreviation of emergency room, by 1965.
era (n.) Look up era at Dictionary.com
1716, earlier aera (1610s), from Late Latin aera, era "an era or epoch from which time is reckoned," probably identical with Latin aera "counters used for calculation," plural of aes (genitive aeris) "brass, copper, money" (see ore, also compare copper).

The Latin word's use in chronology said to have begun in 5c. Spain (where, for some reason unknown to historians, the local era, aera Hispanica, began 38 B.C.E.; some say it was because of a tax levied that year). Like epoch, in English it originally meant "the starting point of an age;" meaning "system of chronological notation" is c.1640s; that of "historical period" is from 1741, as in the U.S. Era of Good Feeling (which was anything but) in reference to the Monroe Administration (1817-24), attested from 1817.
eradicate (v.) Look up eradicate at Dictionary.com
early 15c., from Latin eradicatus, past participle of eradicare "to root out" (see eradication). Related: Eradicated; eradicating; eradicable.
eradication (n.) Look up eradication at Dictionary.com
early 15c., from Latin eradicationem (nominative eradicatio), noun of action from past participle stem of eradicare "root out, extirpate, annihilate," from ex- "out" (see ex-) + radix (genitive radicis) "root" (see radish).
erasable (adj.) Look up erasable at Dictionary.com
1849, from erase + -able.
erase (v.) Look up erase at Dictionary.com
c.1600, from Latin erasus, past participle of eradere "scrape out, scrape off, shave," from ex- "out" (see ex-) + radere "to scrape" (see raze). Of magnetic tape, from 1945. Related: Erased; erasing.
eraser (n.) Look up eraser at Dictionary.com
"thing that erases writing," 1790, American English, agent noun from erase. Originally a knife for scraping off the ink. As a rubber product for removing pencil marks, from 1858.
Erasmus Look up Erasmus at Dictionary.com
masc. proper name, Latin, literally "beloved;" related to Greek erasmios "lovely, pleasant," from eran "to love" (see Eros).
Erastus Look up Erastus at Dictionary.com
masc. proper name, Latin, literally "beloved," from Greek erastos, verbal adjective of eran "to love" (see Eros).
erasure (n.) Look up erasure at Dictionary.com
1734, from erase + -ure.
Erato Look up Erato at Dictionary.com
muse who presided over lyric poetry, from Greek erastos "loved, beloved; lovely, charming," verbal adjective of eran "to love, to be in love with" (see Eros).
erbium (n.) Look up erbium at Dictionary.com
1843, coined in Modern Latin with metallic element name -ium + erbia, name given by Swedish chemist Carl Gustaf Mosander (1797-1858), who discovered it, from second element in Ytterby, name of a town in Sweden where mineral containing it was found.
ere (prep.) Look up ere at Dictionary.com
c.1200, from Old English ær (adv., conj., & prep.) "soon, before (in time)," from Proto-Germanic *airiz, comparative of *air "early" (cognates: Old Saxon, Old Frisian, Old High German er, Dutch eer; German eher "earlier;" Old Norse ar "early;" Gothic air "early," airis "earlier"), from PIE *ayer- "day, morning" (cognates: Avestan ayar "day;" Greek eerios "at daybreak," ariston "breakfast"). The adverb erstwhile retains the Old English superlative ærest "earliest."
Erebus Look up Erebus at Dictionary.com
"place of darkness between earth and Hades," from Latin Erebus, from Greek Erebos, of unknown origin, perhaps from Semitic (compare Hebrew erebh "sunset, evening"), or from PIE *regw-es- "darkness." Used figuratively of darkness from 1590s.
Erechtheus Look up Erechtheus at Dictionary.com
legendary first king and founder of Athens, from Latin Erechtheus, from Greek Erekhtheos, literally "render, shaker" (of the earth), from erekhthein "to rend, break, shatter, shake." Hence, Erechtheum, the name of a temple on the Athenian acropolis.
erect (adj.) Look up erect at Dictionary.com
late 14c., "upright, not bending," from Latin erectus "upright, elevated, lofty; eager, alert, aroused," past participle of erigere "raise or set up," from e- "up" + regere "to direct, keep straight, guide" (see regal).
erect (v.) Look up erect at Dictionary.com
c.1400, a back-formation from erect (adj.) or else from Latin erectus. Related: Erected; erecting.
erectile (adj.) Look up erectile at Dictionary.com
1830, from French érectile, from Latin erect-, past participle stem of erigere (see erect (adj.)).
erection (n.) Look up erection at Dictionary.com
mid-15c., "establishment; advancement," from Late Latin erectionem (nominative erectio), noun of action from past participle stem of erigere (see erect (adj.)). Meaning "the putting up" (of a building, etc.), "stiffening of the penis" are both from 1590s.
erector (n.) Look up erector at Dictionary.com
1530s, agent noun in Latin form from erect (v.).
eremite (n.) Look up eremite at Dictionary.com
c.1200, learned form of hermit (q.v.), from Church Latin eremita. Since mid-17c. in poetic or rhetorical use only, except in reference to specific examples in early Church history. Related: Eremitic; eremitical.
erg (n.1) Look up erg at Dictionary.com
unit of energy in the C.G.S. system, coined 1873 by the British Association for the Advancement of Science from Greek ergon "work" (see organ).
erg (n.2) Look up erg at Dictionary.com
"region of drifting sand dunes," 1875, from French erg (1854), from North African Arabic 'irj, from a Berber word.
ergative Look up ergative at Dictionary.com
1943, grammatical case used for the subjects of transitive verbs (in Eskimo, Basque, Caucasian languages), from Greek ergatos "workman," from ergos "work" (see organ) + -ive.
ergo Look up ergo at Dictionary.com
c.1400, from Latin ergo "therefore, in consequence of," possibly from *ex rogo "from the direction," from ex "out of" (see ex-) + root of regere "to guide" (see regal).
ergonomics (n.) Look up ergonomics at Dictionary.com
"scientific study of the efficiency of people in the workplace," coined 1950 from Greek ergon "work" (see organ) + second element of economics.
ergophobia (n.) Look up ergophobia at Dictionary.com
"fear of work," 1905, coinage by British medical man Dr. William Dunnett Spanton, from Greek ergos "work" (see organ) + -phobia "fear."
Mr. W.D. Spanton (Leeds) considered that the most prominent causes of physical degeneration were--efforts to rear premature and diseased infants, absurd educational high pressure, cigarette smoking in the younger generation, and late hours at night; in fact, the love of pleasure and ergophobia in all classes of society. He considered that there was too much cheap philanthropy, that life was made too easy for the young poor, and that by modern educational methods proper parental discipline was rendered almost impossible. [report on the 73rd annual meeting of the British Medical Association, "Nature," Aug. 3, 1905]