Online Etymology Dictionary

enlargement (n.): 1530s, "a release from confinement," from enlarge in the secondary Middle English sense "release a prisoner" (mid-15c.) + -ment. Meaning "act of increasing in size" is from 1560s. Photographic sense "picture of a larger size than the negative from which it was made" is from 1866.
enlighten (v.): late 14c., "to remove the dimness or blindness" (usually figurative, from one's eyes or heart); see en- (1) + lighten. From 1660s as "supply with intellectual light." Literal senses are later and less common in English: "put light in" is from 1580s; "shed light upon" is from 1610s. Related: Enlightened; enlightening. Old English had inlihtan "to illuminate, enlighten."
enlightened (adj.): 1630s, "illuminated;" 1660s in the sense "well-informed;" past participle adjective from enlighten.
enlightenment (n.): 1660s, "action of enlightening," from enlighten + -ment. Used only in figurative sense, of spiritual enlightenment, etc. Attested from 1865 as a translation of German Aufklärung, a name for the spirit of independent thought and rationalistic system of 18c. Continental philosophers.
For the philosophes, man was not a sinner, at least not by nature; human nature -- and this argument was subversive, in fact revolutionary, in their day -- is by origin good, or at least neutral. Despite the undeniable power of man's antisocial passions, therefore, the individual may hope for improvement through his own efforts -- through education, participation in politics, activity in behalf of reform, but not through prayer. [Peter Gay, "The Enlightenment"]
enlist (v.): also inlist, 1690s (trans.), 1753 (intrans.), from en- (1) "make, put in" + list (n.1). Possibly suggested by Dutch inlijsten "to write on a list." Related: Enlisted; enlisting.
enlistment (n.): 1758, from enlist + -ment.
enliven (v.): 1630s, "give life to," from en- (1) "make, put in" + live for life + -en (1). Meaning "make lively or cheerful" is from 1690s. Related: Enlivened; enlivening. Enlive in same sense is from 1590s. A noun, enlivement, is recorded from 1877.
enmesh (v.): c. 1600, from en- (1) "put in" + mesh (v.). Related: Enmeshed; enmeshing.
enmity (n.): late 14c., "hostile feeling, rivalry, malice; internal conflict," from Old French enemite, variant of enemistié "enmity, hostile act, aversion" (Modern French inimité), from Vulgar Latin *inimicitatem (nominative *inimicitas), from Latin inimicitia "enmity, hostility," usually plural, from inimicus "enemy" (see enemy). Related: Enmities. Amity is basically the same word without the negative prefix.
ennead (n.): "group of nine things," 1650s, from Greek enneas (genitive enneados) "group of nine," from ennea "nine" (see nine). Especially in reference to the divisions of Porphyry's collection of the neo-Platonic doctrines of Plotinus. Related: enneadic.
ennoble (v.): late 15c., "refine, impart a higher character to" (implied in ennobled), from Middle French ennoblir; see en- (1) + noble (adj.). Sense of "give noble rank to" is from 1590s. Related: Ennobler; ennobling.
ennui (n.): 1660s as a French word in English; nativized by 1758; from French ennui, from Old French enui "annoyance" (13c.), back-formation from enuier (see annoy). Hence ennuyé (adj.) "afflicted with ennui," and thence ennuyée (n.) for a woman so afflicted.
So far as frequency of use is concerned, the word might be regarded as fully naturalized; but the pronunciation has not been anglicized, there being in fact no Eng. analogy which could serve as a guide. [OED]
Enoch: masc. proper name, in Old Testament eldest son of Cain, father of Methuselah, from Latin Enoch, from Greek Enokh, from Hebrew Hanokh, literally "dedicated, consecrated," from hanakh "he dedicated," whence also Hanukkah. Related: Enochian.
enoptomancy (n.): divination by means of a mirror, 1855, from Greek enoptos, literally "seen in," from en- "in" (see in) + optos "seen, visible" (see optic) + -mancy.
enormious (adj.): see enormous.
enormity (n.): late 15c., "transgression, crime; irregularity," from Old French enormité "extravagance, atrocity, heinous sin," from Latin enormitatem (nominative enormitas) "hugeness, vastness; irregularity," from enormis "irregular, huge" (see enormous). Meaning "extreme wickedness" in English attested from 1560s. The notion is of that which surpasses the endurable limits of order, right, decency. Sense of "hugeness" (1765 in English) is etymological but to prevent misunderstanding probably best avoided in favor of enormousness, though this, too, originally meant "immeasurable wickedness" (1718) and didn't start to mean "hugeness" until c. 1800.
enormous (adj.): 1530s, "abnormal" (usually in a bad sense), from Latin enormis "out of rule, irregular, shapeless; extraordinary, very large," from assimilated form of ex- "out of" (see ex-) + norma "rule, norm" (see norm), with English -ous substituted for Latin -is. Meaning "extraordinary in size" is attested from 1540s; original sense of "outrageous" is more clearly preserved in enormity. Earlier was enormyous (mid-15c.) "exceedingly great, monstrous." Related: Enormously; enormousness.
Enos: masc. proper name, in Old Testament the son of Seth, from Greek Enos, from Hebrew Enosh, literally "man" (compare nashim "women," Arabic ins "men, people").
enough (adj.): c. 1300, from Old English genog "sufficient in quantity or number," from Proto-Germanic compound *ganoga- "sufficient" (source also of Old Saxon ginog, Old Frisian enoch, Dutch genoeg, Old High German ginuog, German genug, Old Norse gnogr, Gothic ganohs).

First element is Old English ge- "with, together" (also a participial, collective, intensive, or perfective prefix), making this word the most prominent surviving example of the Old English prefix, the equivalent of Latin com- and Modern German ge- (from PIE *kom- "beside, near, by, with;" see com-). Second element is from PIE *nok-, from root *nek- (2) "to reach, attain" (source also of Sanskrit asnoti "reaches," Hittite ninikzi "lifts, raises," Lithuanian nešti "to bear, carry," Latin nancisci "to obtain").

As an adverb, "sufficiently for the purpose," in Old English; meaning "moderately, fairly, tolerably" (good enough) was in Middle English. Understated sense, as in have had enough "have had too much" was in Old English (which relied heavily on double negatives and understatement). As a noun in Old English, "a quantity or number sufficient for the purpose." As an interjection, "that is enough," from c. 1600. Colloquial 'nough said is attested from 1839.
enow (adj., n.): Old English genoge (plural adjective), from genog (see enough). By Johnson, regarded as the plural of enough.
enquire (v.): alternative form of inquire, according to OED mainly used in sense of "to ask a question." Related: enquired; enquiring.
enquiry (n.): alternative spelling of inquiry. Also see enquire. Related: Enquiries.
enrage (v.): late 14c., "make furious or mad" (implied in enraged), from Old French enragier "go wild, go mad, lose one's senses," from en- "make, put in" (see en- (1)) + rage "rabies, rage" (see rage (n.)). Related: Enraging. Intransitive only in Old French; but the transitive sense is oldest and predominant in English.
enrapt (adj.): c. 1600, "carried away by (prophetic) ecstasy," from en- "make, put in" (see en- (1)) + rapt.
enrapture (v.): 1740, from en- (1) "put in" + rapture (n.). Related: Enraptured.
enrich (v.): late 14c., "to make wealthy," from Old French enrichir "enrich, enlarge," from en- "make, put in" (see en- (1)) + riche "rich" (see rich). Figurative sense "supply with abundance of something desirable" is from 1590s. Meaning "to fertilize" is from c. 1600. Scientific sense of "to increase the abundance of a particular isotope in some material" is first attested 1945. Related: Enriched; enriching.
enrichment (n.): 1620s, from enrich + -ment.
enrobe (v.): 1590s, from en- (1) "in" + robe (n.). Related: Enrobed; enrobing.
enrol (v.): alternative spelling of enroll. Related: Enroled; enroling.
enroll (v.): mid-14c. (transitive), from Old French enroller "record in a register, write in a roll" (13c., Modern French enrôler), from en- "make, put in" (see en- (1)) + rolle (see roll (n.)). Related: Enrolled; enrolling.
enrollment (n.): also enrolment, mid-15c., "act of enrolling," from Anglo-French enrollement, from Middle French enrollement, from Old French enroller "record in a register" (see enroll). Meaning "total number enrolled" is from 1859, American English.
ensample (n.): "precedent to be followed, illustrative instance; a pattern, model," c. 1300, variant of asaumple, from Old French essample "example" (see example). The survival of this variant form is due to its use in New Testament in KJV (1 Pet. v.3).
ensconce (v.): 1580s, "to cover with a fort," from en- (1) "make, put in" + sconce "small fortification, shelter," perhaps via French, probably from Dutch schans "earthwork" (compare Middle High German schanze "bundle of sticks"), which is of uncertain origin. Hence, "to fix firmly, settle" (1590s). Related: Ensconced.
ensemble (n.): 1703, "union of parts, parts of a thing taken together," from French ensemblée "all the parts of a thing considered together," from Late Latin insimul "at the same time," from in- intensive prefix + simul "at the same time," related to similis (see similar). Musical sense of "union of all parts in a performance" in English first attested 1844. Of women's dress and accessories, from 1927. Earlier in English as an adverb (mid-15c.), "together, at the same time."
enshrine (v.): in early use also inshrine, 1580s, from en- (1) "make, put in" + shrine (n.). Related: Enshrined; enshrining.
enshroud (v.): 1580s, from en- (1) "make, put in" + shroud (n.). Related: Enshrouded; enshrouding.
ensign (n.): early 15c., "a token, sign, symbol; badge of office, mark or insignia of authority or rank;" also "battle flag, flag or banner of a ship or troop of soldiers," via Scottish, from Old French enseigne (12c.) "mark, symbol, signal; flag, standard, pennant," from Latin insignia (plural); see insignia, which is a doublet of this word. As the word for the soldier who carries the flag, 1510s. U.S. Navy sense of "commissioned officer of the lowest rank" is from 1862. French navy had rank of enseigne de vaisseau since at least early 18c. Until 1871 one of the lowest grades of commissioned officers in a British army infantry regiment, also a rank in the American Revolutionary army.
ensilage (n.): 1879, from French ensilage, from ensiler "put in a silo," from Spanish ensilar (see silo).
enslave (v.): 1640s, from en- (1) "make, make into" + slave (n.). Related: Enslaved; enslaving.
enslavement (n.): 1690s, from enslave + -ment.
ensnare (v.): formerly also insnare, 1570s, from en- (1) "make, put in" + snare (n.). Related: Ensnared; ensnaring.
ensorcell (v.): also ensorcel, "to bewitch," 1540s, from French ensorceller, from Old French ensorceler, dissimilated from ensorcerer from en- (see en- (1)) + verb from sorcier "sorcerer, wizard" (see sorcery). Related: Ensorcelled; ensorceled.
ensue (v.): c. 1400, "seek after, pursue; follow (a path)," from Old French ensu-, past participle stem of ensivre "follow close upon, come afterward," from Late Latin insequere, from Latin insequi "to pursue, follow, follow after; come next," from in- "upon" (see in- (2)) + sequi "follow" (see sequel). Early 15c. as "follow (as a consequence), to result;" mid-15c. as "to follow" in time or space, "to come or appear next, be subsequent to, happen subsequently." Related: Ensued; ensues; ensuing.
ensure (v.): late 14c., from Anglo-French enseurer, from en- "make" (see en- (1)) + Old French seur "sure" (see sure); probably influenced by Old French asseurer "assure." Compare insure. Related: Ensured; ensures; ensuring.
entablature (n.): 1610s, in architecture, nativization of Italian intavolatura; see en- (1) + tablature.
entail (v.): mid-14c., "convert (an estate) into 'fee tail' (feudum talliatum)," from en- (1) "make" + taile "legal limitation," especially of inheritance, ruling who succeeds in ownership and preventing the property from being sold off, from Anglo-French taile, Old French taillie, past participle of taillier "allot, cut to shape," from Late Latin taliare "to split" (see tailor (n.)). Sense of "have consequences" is 1829, via the notion of "inseparable connection." Related: Entailed; entailling; entailment.
entangle (v.): early 15c., from en- (1) + tangle (n.). Related: Entangled; entangling.
entanglement (n.): 1630s, "that which entangles," from entangle + -ment. From 1680s as "act of entangling." Foreign entanglements does not appear as such in Washington's Farewell Address (1796), though he warns against them. The phrase is found in William Coxe's 1798 memoirs of Sir Robert Walpole.
entelechy (n.): c. 1600, from Latinized form of Greek entelekheia "actuality," from en "in" (see en- (2)) + telei, dative of telos "perfection" (see tele-) + ekhein "to have" (see scheme (n.)). In Aristotle, "the condition in which a potentiality has become an actuality."
entente (n.): "an understanding," 1854, from French éntente "an understanding," from Old French entente "intent, intention; attention; aim, goal" (12c.), noun use of fem. past participle of entendre "to direct one's attention" (see intent). Political sense arose in 19c. from entente cordiale (1844); the best-known example was that between England and France (1904), to which Russia was added in 1908.