Online Etymology Dictionary

effluvium (n.): 1640s, from Latin effluvium "a flowing out, an outlet," from effluere "to flow out" (see effluence). Related: Effluvial.
efflux (n.): 1640s, "act or state of flowing out," also "that which flows out," from Latin effluxus, past participle of effluere "to flow out" (see effluence).
effort (n.): late 15c., "laborious attempt, strenuous exertion," from Middle French effort, from Old French esforz "force, impetuosity, strength, power," verbal noun from esforcier "force out, exert oneself," from Vulgar Latin *exfortiare "to show strength" (source of Italian sforza), from Latin ex- "out" (see ex-) + Latin fortis "strong" (see fort).
Effort is only effort when it begins to hurt. [Ortega y Gasset, 1949]
Related: Efforts "voluntary exertion," also "result of exertion."
effortless (adj.): 1752, "passive, making no effort," from effort + -less. Meaning "easy, requiring no effort" is from 1810. Related: Effortlessly; effortlessness.
effrontery (n.): "shamelessness, impudence, boldness in transgressing the bounds of modesty and propriety," 1715, from French effronterie, from effronté "shameless," from Old French esfronte "shameless, brazen," probably from Late Latin effrontem (nominative effrons) "barefaced, shameless," from Latin ex- "out" (see ex-) + frontem (nominative frons) "brow" (see front (n.)). Also compare affront.

Latin frontus had a sense of "ability to blush," but the literal sense of effrontery often has been taken to be "putting forth the forehead." Forehead in Johnson's Dictionary (1755) has a secondary sense of "impudence; confidence; assurance; audaciousness; audacity." English had an earlier verb effront "treat with effrontery" (17c.).
effulgence (n.): 1660s (Milton), from Late Latin effulgentia (from Latin effulgentum; see effulgent).
effulgent (adj.): 1738, back-formation from effulgence, or else from Latin effulgentem (nominative effulgens), present participle of effulgere "to shine out, gleam forth," from ex "out" (see ex-) + fulgere "to shine" (see bleach (v.)). Related: Effulgently.
effuse (v.): "to pour out, spill," late 14c., from Middle French effuser or directly from Latin effusus "poured out," past participle of effundere "to pour forth" (see effusion). Related: Effused; effusing. Not to be confused with eff youse.
effuse (adj.): 1520s, from Latin past participle adjective effusus "poured out," also "extensive, vast, broad, wide" (see effuse (v.)).
effusion (n.): c. 1400, "a pouring out," from Middle French effusion (14c.) and directly from Latin effusionem (nominative effusio) "a pouring forth," noun of action from past participle stem of effundere "pour forth, spread abroad; to lavish, squander, waste," from ex- "out" (see ex-) + fundere "pour" (see found (v.2)). Figuratively, of speech, emotion, etc., from 1650s.
effusive (adj.): "flowing profusely" (especially of words), 1660s, from Latin effus-, stem of effundere "to pour forth, spread abroad" (see effusion) + -ive. Hence, "with extravagant display of feelings" (1863). Related: Effusively.
eft (n.): Old English efte, efeta "small lizard-like animal," of unknown origin (see newt).
eftsoons (adv.): obsolete or archaic way of saying "soon afterward," from Old English eftsona "a second time, repeatedly, soon after, again," from eft "afterward, again, a second time" (from Proto-Germanic *aftiz, from PIE root *apo- "off, away;" see apo-) + sona "immediately" (see soon). With adverbial genitive. Not in living use since 17c.
egad (interj.): 1670s, I gad, a softened oath, second element God, first uncertain; perhaps it represents exclamation ah.
egalitarian (adj.): 1881, from French égalitaire, from Old French egalite "equality," from Latin aequalitatem (see equality). Originally often in egalitarian despotism, such as the government resulting from the French Revolution or the ideas of the communists. The noun, "person who favors egalitarianism," is from 1920.
egalitarianism (n.): 1884, from egalitarian + -ism.
Egbert: masc. proper name, from Old English Ecg-beorht, literally "sword-bright." See edge (n.) + bright (adj.).
egest (v.): "to discharge, pass off, expel," especially "defecate," c. 1600, from Latin egestus, past participle of egerere "to bring out, discharge, vomit," from assimilated form of ex- "out" (see ex-) + gerere "to carry, bear" (see gest). The opposite of ingest. Related: Egested; egesting; egesta.
egestion (n.): "act of voiding the refuse of digestion," early 15c., from Latin egestionem (nominative egestio), noun of action from past participle stem of egerere "to discharge" (see egest).
egg (n.): mid-14c., egge, mostly in northern England dialect, from Old Norse egg, from Proto-Germanic *ajja(m) (source also of Old Saxon, Middle Dutch, Dutch, Old High German, German ei, Gothic ada), probably from PIE *owyo-/*oyyo- "egg" (source also of Old Church Slavonic aja, Russian jajco, Breton ui, Welsh wy, Greek oon, Latin ovum); possibly derived from root *awi- "bird."

This Norse-derived northern word vied in Middle English with native cognates eye, eai, from Old English æg, until finally displacing the others after c. 1500. Caxton (15c.) writes of a merchant (probably a north-country man) in a public house on the Thames who asked for eggs:
And the goode wyf answerde, that she coude speke no frenshe. And the marchaunt was angry, for he also coude speke no frenshe, but wolde have hadde egges, and she understode hym not.
She did, however, recognize another customer's request for "eyren." Used of persons from c. 1600. Bad egg in the figurative sense is from 1855; bad eggs aren't always obvious to outward view (there was an old proverb, "bad bird, bad egg"). To have egg on (one's) face "look foolish" is attested by 1948.
[Young & Rubincam] realize full well that a crew can sometimes make or break a show. It can do little things to ruin a program or else, by giving it its best, can really get that all-important rating. They are mindful of an emcee of a variety show who already has been tabbed "old egg in your face" because the crew has managed to get him in such awkward positions on the TV screen. ["Billboard," March 5, 1949]
Eggs Benedict attested by 1898. The figure of speech represented in to have all (one's) eggs in one basket is attested by 1660s. The conundrum of the chicken (or hen) and the egg is attested from 1875.
Bumble, bramble, which came first, sir,
Eggs or chickens? Who can tell?
I'll never believe that the first egg burst, sir,
Before its mother was out of her shell.

[Mary Mapes Dodge, "Rhymes and Jingles," N.Y., 1875]
egg (v.): c. 1200, from Old Norse eggja "to goad on, incite," from egg "edge" (see edge (n.)). The unrelated verb meaning "to pelt with (rotten) eggs" is from 1857, from egg (n.). Related: Egged; egging.
egg-beater (n.): also eggbeater, 1828, from egg (n.) + beater. Slang sense of "helicopter" is from 1937 from notion of whirling rotation.
egg-cup (n.): 1773, from egg (n.) + cup (n.).
egg-nog (n.): also eggnog, c. 1775, American English, from egg (n.) + nog "strong ale."
egg-timer (n.): 1873, from egg (n.) + timer.
egg-white (n.): 1898, from egg (n.) + white (n.).
egghead (n.): also egg-head, 1907, "bald person," from egg (n.) + head (n.). Sense of "intellectual" is attested from 1918, among Chicago newspapermen; popularized by U.S. syndicated columnist Stewart Alsop in 1952 in reference to Adlai Stevenson's presidential campaign.
Adlai Stevenson once told what it was like to be the rare intellectual in politics. "Via ovicapitum dura est," he said, the way of the egghead is hard. [New York Times, Oct. 28, 1982]
eggplant (n.): also egg-plant, 1763, from egg (n.) + plant (n.). Originally of the white variety. Compare aubergine.
eggshell (n.): also egg-shell, early 15c., from egg (n.) + shell (n.). It displaced ay-schelle (Old English ægscill), from the native word for "egg." As a color term, from 1894. Emblematic of "thin and delicate" from 1835; the figure of treading on eggshells "to move cautiously" is attested by 1734.
eglantine (n.): "sweet briar," c. 1400, from French églantine, from Old French aiglent "dog rose," from Vulgar Latin *aquilentus "rich in prickles," from Latin aculeus "spine, prickle," diminutive of acus "needle" (see acuity).
ego (n.): 1714, as a term in metaphysics, "the self; that which feels, acts, or thinks," from Latin ego "I" (cognate with Old English ic; see I). Psychoanalytic (Freudian) sense is from 1894; sense of "conceit" is 1891. Ego-trip first recorded 1969, from trip (n.). Related: egoical; egoity.
In the book of Egoism it is written, Possession without obligation to the object possessed approaches felicity. [George Meredith, "The Egoist," 1879]
egocentric (adj.): 1890, from ego + -centric. Related: Egocentricity; egocentrism.
egoism (n.): 1785, in metaphysics, "the theory that a person has no proof that anything exists outside his own mind," from French égoisme (1755), from Modern Latin egoismus, from Latin ego (see ego). Meaning "doing or seeking of that which affords pleasure or advances interest" is from 1800; opposed to altruism, but not necessarily "selfish." Meaning "self-centeredness" is from 1840. Between egoism and egotism, egoism is more correctly formed; there formerly was a useful distinction, with egotism tending to take the senses "self-centeredness" and "extensive use of 'I'" and leaving to egoism the theoretical sense in metaphysics and ethics.
egoist (n.): 1763, in metaphysics, "one who maintains there is no evidence of the existence of anything but the self" (taking ego in a sense of "thinking subject"), from French égoiste (1755); see ego + -ist. Meaning "selfish person" is from 1879. Related: Egoistic; egoistical.
egomania (n.): 1825, from ego + mania.
egomaniac (n.): 1890, from egomania. Related: Egomaniacal.
egotheism (n.): "deification of the self," 1855, from ego + theism. Related: Egotheist (1849); egotheistic.
egotism (n.): 1714, "too frequent use of 'I'," from ego + -ism. First used by Joseph Addison, who credits the term to "Port-Royalists" who used it in reference to obtrusive use of first person singular pronoun in writing, hence "talking too much about oneself." Meaning "self-conceit, selfishness" is from 1800. The -t- is abnormal, perhaps by influence of dogmatism.
egotist (n.): 1714, "one who makes too frequent use of the first-person singular pronoun," see ego + -ist. First attested in Joseph Addison (see egotism). Related: Egotistic; egotistical; egotistically.
egotize (v.): "talk overmuch of oneself," 1775, from ego + -ize.
egregious (adj.): 1530s, "distinguished, eminent, excellent," from Latin egregius "distinguished, excellent, extraordinary," from the phrase ex grege "rising above the flock," from ex "out of" (see ex-) + grege, ablative of grex "herd, flock" (see gregarious).

Disapproving sense, now predominant, arose late 16c., originally ironic. It is not in the Latin word, which etymologically means simply "exceptional." Related: Egregiously; egregiousness.
egress (n.): 1530s, "act of going out," from Latin egressus "a going out," noun use of past participle of egredi "go out," from ex- "out" (see ex-) + -gredi, comb. form of gradi "step, go" (see grade (n.)). Perhaps a back-formation from egression (early 15c.). Meaning "place of exit" is from 1670s. "One who goes out" is an egressor.
egret (n.): mid-14c., from Old French aigrette, from Old Provençal aigreta, diminutive of aigron "heron," perhaps of Germanic origin (compare Old High German heigaro; see heron).
Egypt: Old English Egipte "the Egyptians," from French Egypte, from Greek Aigyptos "the river Nile, Egypt," from Amarna Hikuptah, corresponding to Egyptian Ha(t)-ka-ptah "temple of the soul of Ptah," the creative god associated with Memphis, the ancient city of Egypt.

Strictly one of the names of Memphis, it was taken by the Greeks as the name of the whole country. The Egyptian name, Kemet, means "black country," possibly in reference to the rich delta soil. The Arabic is Misr, which is derived from Mizraim, the name of a son of Biblical Ham.
Egyptian: late 14c., Egypcyan, adjective and noun; see Egypt + -ian. Old English had Egiptisc. Meaning "the language of Egypt" is from 1550s.
Egyptology (n.): 1841, from Egypt + -ology. Related: Egyptologist.
eh: 1560s as an exclamation of sorrow; as an exclamation of inquiry, doubt, or slight surprise, usually with questions, from 1773.
eider (n.): type of duck, 1743, from German Eider or Dutch eider, both from Old Norse æþar, genitive of æþr "duck," according to Watkins from a North Germanic root *athi-, from Proto-Germanic *ethi-, from PIE "probable root" *eti- "eider duck."
eiderdown (n.): "soft feathers of the eider-duck" (such as it uses to line its nest), 1774; see eider + down (n.1). Ultimately from Icelandic æðardun, via a Scandinavian source (compare Danish ederdunn) or German Eiderdon.
eidetic (adj.): "pertaining to the faculty of projecting images," 1924, from German eidetisch, coined by German psychologist Erich Jaensch (1883-1940), from Greek eidetikos "pertaining to images," also "pertaining to knowledge," from eidesis "knowledge," from eidos "form, shape" (see -oid).