Online Etymology Dictionary

elopement (n.): 1540s, from elope + -ment. (The word was in Anglo-French in 14c. as alopement).
eloquence (n.): late 14c., from Old French eloquence (12c.), from Latin eloquentia, from eloquentem (nominative eloquens) "eloquent," present participle of eloqui "speak out," from ex- "out" (see ex-) + loqui "to speak" (see locution). Earlier in same sense was eloquency (mid-14c.).
eloquent (adj.): late 14c., from Old French eloquent, from Latin eloquentem (nominative eloquens) "speaking, having the faculty of speech; eloquent," present participle of eloqui "to speak out" (see eloquence). Related: Eloquently.
Elsa: fem. proper name, from German diminutive of Elisabet (see Elizabeth).
else (adv.): Old English elles "in another manner, other, otherwise, besides, different," from Proto-Germanic *aljaz (source also of Gothic aljis "other," Old High German eli-lenti, Old English el-lende, both meaning "in a foreign land;" see also Alsace), an adverbial genitive of the neuter of PIE root *al- (1) "beyond" (source also of Greek allos "other," Latin alius; see alias (adv.)). As a quasi-adjective, synonymous with other, from 1660s; the nuances of usage are often arbitrary.

Productive of a number of handy compounds that somehow never got traction or have been suffered to fall from use: elsehow (1660s) "somehow or other;" elsewards (adv.), 1882, "somewhere else;" Old English elsewhat (pron.) " something else, anything else;" elsewhen (adv.), early 15c., "at another time; elsewhence (c. 1600); elsewho (1540s). Among the survivors are elsewhere, elsewise. Menacing or else, with omitted but implied threat, is from 1833.
Elsevier (n.): early 18c., Elzevir (via French Elzévir), from Dutch Elsevier, the name of a family of Dutch printers famed for the accuracy and elegance of their work; especially in reference to editions of the classics and other works published by them c. 1580-1680.
elsewhere (n.): "in another place, in other places," c. 1400, elswher, from Old English elles hwær (see else + where). Related: Elsewhither (Old English elleshwider.
elsewise (adv.): "in a different manner, otherwise," 1540s, from else + -wise.
elucidate (v.): 1560s, perhaps via Middle French élucider (15c.) or directly from Late Latin elucidatus, past participle of elucidare "make light or clear," from assimilated form of ex- "out, away" (see ex-) + lucidus "clear" (see lucid). Related: Elucidated; elucidates; elucidating.
elucidation (n.): 1560s, "act of making intelligible," noun of action from elucidate. As "an explanation" from 1660s.
elude (v.): 1530s, "delude, make a fool of," from Latin eludere "finish play, win at play; escape from or parry (a blow), make a fool of, mock, frustrate; win from at play," from assimilated form of ex- "out, away" (see ex-) + ludere "to play" (see ludicrous). Sense of "evade" is first recorded 1610s in a figurative sense, 1630s in a literal one. Related: Eluded; eludes; eluding.
elusion (n.): "deception, escape by artifice or deceit," 1540s, noun of action from elude, or from Medieval Latin elusionem (nominative elusio), noun of action from past participle stem of Latin eludere.
elusive (adj.): 1719, from Latin elus-, past participle stem of eludere "elude, frustrate" (see elude) + -ive. Related: Elusiveness.
elution (n.): "washing, purification," 1610s, from Late Latin elutionem (nominative elutio) "a washing out," noun of action from past participle stem of Latin eluere "to wash out, wash off, clean," from ex- "out" (see ex-) + luere "to wash" (see lave). Especially in reference to a process of obtaining sugar from molasses.
elven (adj.): Old English -ælfen (n.) "an elf or fairy," usually a female one (see elf). Not a pure adjective in Middle English (elvish was used), but used in phrases such as elven land (c. 1300). Apparently revived as an adjective by Tolkien (1937).
elver (n.): "young eel," 1640s, variant or corruption of eelfare (1530s), literally "passage of young eels up a river;" see eel + fare (n.).
Elvira: fem. proper name, from Spanish, of Germanic origin.
elvish (adj.): c. 1200, aluisc, "belonging to or pertaining to the elves; supernatural," from elf + -ish. Old English used ilfig in this sense.
Elysian (adj.): 1570s, "pertaining to Elysium (q.v.), the abode of the blessed after death." Hence, "exquisitely happy, full of the highest bliss."
Elysium (n.): 1590s, from Latin Elysium, from Greek Elysion (pedion) "Elysian field," abode of the blessed after death, where heroes and the virtuous dwell, which is of unknown origin, perhaps from a pre-Greek language. Also used figuratively of a situation of complete happiness.
elytra (n.): 1774, plural of elytron "hardened wing of an insect," from Greek elytron "sheath," from elyein "to roll round," from PIE root *wel- (3) "to turn, roll," with derivatives referring to curved, enclosing objects (see volvox). Related: Elytroid.
elytro-: word-forming element used for "vagina" in medical terms, from Greek elytron, literally "sheath" (see elytra). Related: Elytral.
em (n.): name of the letter M, c. 1200, from Latin; the Greek name was mu. In printing, originally the square corresponding in dimensions to the capital M of that type.
em-: word-forming element meaning "put in or into, bring to a certain state," sometimes intensive, from French assimilation of en- "in, into" (see en- (1)) to following labial stop (-b-, -p-, and often -m-), or from the same development in later Latin in- (to im-). "This rule was not fully established in spelling before the 17th c." [OED], but it is likely the pronunciation shift was in Old French and Middle English and spelling was slow to conform. Also a living prefix in English used to form verbs from adjectives and nouns (embitter, embody). In words such as emancipate, emerge, emit, emotion the e- is a reduced form of Latin ex- (see ex-) before -m-.
emaciate (v.): 1620s "cause to lose flesh" (implied in emaciating), from Latin emaciatus, past participle of emaciare "make lean, cause to waste away," from assimilated form of ex- "out" (see ex-) + macies "leanness," from macer "thin" (see macro-). Intransitive meaning "become lean, waste away" is from 1640s. Related: Emaciated.
emaciated (adj.): 1660s, past participle adjective from emaciate.
emaciation (n.): 1660s, from Latin emaciationem, noun of state from past participle stem of emaciare (see emaciate), or perhaps a native formation from emaciate.
emaculate (v.): "remove blemishes from," 1620s, from Latin emaculatus "freed from blemishes," past participle of emaculare, from assimilated form of ex- (see ex-) + maculare (see maculate (adj.)).
email (n.): type of pottery design pattern, 1877, from French email, earlier esmail (12c.), literally "enamel" (see enamel (n.)). Also now a variant of e-mail.
emanant (n.): 1852, in mathematics, from Latin emanantem (nominative emanans), present participle of emanare (see emanate).
emanate (v.): 1680s, "to flow out," from Latin emanatus, past participle of emanare "flow out," figuratively "arise from, proceed from" (see emanation). Related: Emanated; emanating.
emanation (n.): 1560s, from Late Latin emanationem (nominative emanatio), noun of action from past participle stem of Latin emanare "flow out, spring out of," figuratively "arise, proceed from," from assimilated form of ex- "out" (see ex-) + manare "to flow," from PIE root *ma- (3) "damp."
emancipate (v.): 1620s, "set free from control," from Latin emancipatus, past participle of emancipare "put (a son) out of paternal authority, declare (someone) free, give up one's authority over," in Roman law, the freeing of a son or wife from the legal authority (patria potestas) of the pater familias, to make his or her own way in the world; from assimilated form of ex- "out, away" (see ex-) + mancipare "deliver, transfer or sell," from mancipum "ownership," from manus "hand" (see manual (adj.)) + capere "take" (see capable). Related: Emancipated; emancipating.

Not used by the Romans in reference to the freeing of slaves, the verb for this being manumittere. The English word was adopted in the jargon of the cause of religious toleration (17c.), then anti-slavery (1776). Also used in reference to women who free themselves from conventional customs (1850).
emancipated (adj.): 1726, "set free," past participle adjective from emancipate (v.). Meaning "freed from custom or social restraints" is from 1850.
emancipation (n.): 1630s, "a setting free," from French émancipation, from Latin emancipationem (nominative emancipatio), noun of action from past participle stem of emancipare (see emancipate). In modern use especially of the freeing of a minor from parental control. Specifically with reference to U.S. slavery from 1785 (the Emancipation Proclamation was issued July 22, 1862, effective Jan. 1, 1863). In Britain, with reference to easing of restrictions on Catholics, etc.
emancipator (n.): 1782, agent noun in Latin form from emancipate. Emancipationist "one who favors emancipation" in any sense is from 1822.
emancipatory (adj.): 1650s; see emancipate + -ory.
emarginate (adj.): "having the margin or extremity notched," 1731 (implied in emarginated), from Latin emarginatus, past participle of emarginare, from assimilated form of ex- (see ex-) + margo "edge, brink, border, margin" (see margin (n.)). Related:" Emargination.
emasculate (v.): c. 1600, from Latin emasculatus, past participle of emasculare "castrate," from assimilated form of ex- "out, away" (see ex-) + masculus "male, manly" (see masculine). Originally and usually in a figurative sense in English. Related: Emasculated; emasculating.
emasculation (n.): 1620s, noun of action from emasculate.
embalm (v.): late 14c., embaumen "to apply balm or ointment; to embalm a corpse," from Old French embaumer, earlier embausmer, "preserve (a corpse) with spices," from assimilated form of en- "in" (see en- (1)) + baume "balm" (see balm) + verbal suffix -er. The -l- inserted in English 1500s in imitation of Latin. Related: Embalmed; embalming.
embankment (n.): 1786, from embank "to enclose with a bank" (1570s; see em- (1) + bank (n.2)) + -ment.
embargo (n.): "order forbidding ships from certain other nations from entering or leaving a nation's ports," 1590s, from Spanish embargo "seizure, arrest; embargo," noun of action from embargar "restrain, impede, arrest, embargo," from Vulgar Latin *imbarricare, from assimilated form of in- "into, upon" (see in- (2)) + *barra (see bar (n.1)). As a verb, from 1640s. Related: Embargoed.
embark (v.): 1540s (transitive); 1570s (intransitive), from Middle French embarquer, from assimilated form of en- "in" (see en- (1)) + barque "small ship" (see bark (n.)). Related: Embarked; embarking.
embarkation (n.): 1640s, from French embarcation, noun of action from embarquer (see embark) or from Spanish embarcacion.
embarras (n.): "embarrassment," 1660s, from French embarras "obstacle;" see embarrass.
embarrass (v.): 1670s, "perplex, throw into doubt," from French embarrasser (16c.), literally "to block," from Italian imbarrazzo, from imbarrare "to bar," from assimilated form of in- "into, upon" (see in- (2)) + Vulgar Latin *barra "bar" (see bar (n.1)).

Meaning "to hamper, hinder" is from 1680s. Meaning "make (someone) feel awkward" first recorded 1828. Original sense preserved in embarras de richesse (1751), from French (1726): the condition of having more wealth than one knows what to do with. Related: Embarrassed; embarrassing; embarrassingly.
embarrassed (adj.): "perplexed, confused," 1680s, past participle adjective from embarrass.
embarrassment (n.): 1670s, "state of being impeded, obstructed, or entangled" (of affairs, etc.), from embarrass + -ment, or from French embarrassement, from embarrasser.

As "a mental state of unease," from 1774. Meaning "thing which embarrasses" is from 1729. Earlier words expressing much the same idea include baishment "embarrassment, confusion" (late 14c.); baishednesse (mid-15c.).
embassador (n.): identified by OED 2nd ed. print as a variant of ambassador "still preferred" in the U.S., though Craigie (1940) points out this is "no longer true."