Online Etymology Dictionary

employ (v.): early 15c., "apply or devote (something to some purpose); expend or spend," from Old French emploiier (12c.) "make use of, apply; increase; entangle; devote," from Latin implicare "enfold, involve, be connected with, unite, associate," from assimilated form of in- (see in- (2)) + plicare "to fold" (see ply (v.1)). Imply, which is the same word, retains more of the original sense. Sense of "hire, engage" first recorded in English 1580s, from meaning "involve in a particular purpose," which arose in Late Latin. Related: Employed; employing; employable.
employ (n.): 1660s, "action of employing," from French emploi, from Middle French verb employer (see employ (v.)). From 1709 as "state of being employed."
employe (n.): "person employed," 1834, from French employé (fem. employée), noun use of past participle of employer (see employ).
employee (n.): "person employed," 1850, mainly in U.S. use, from employ + -ee. Formed on model of French employé.
employer (n.): 1590s, agent noun from employ.
employment (n.): mid-15c., "the spending of money," from Middle English emploien (see employ) + -ment.
emporium (n.): 1580s, "place of trade, mart," from Latin emporium, from Greek emporion "trading place, market," from emporos "merchant," originally "traveler," from assimilated form of en "in" (see en- (2)) + poros "passage, voyage," related to peirein "to pass through" (see port (n.1)). Greek emporos in the "merchant" sense meant especially "one who trades on a large scale, usually but not necessarily by sea" [Buck], as opposed to kapelos "local retail dealer, shopkeeper." Properly, a town which serves as the commercial hub of a region, but by 1830s American English "Grandiloquently applied to a shop or store" [Craigie].
empower (v.): 1650s, also impower, from assimilated form of en- (1) + power (n.). Used by Milton, Beaumont, Pope, Jefferson, Macaulay, but the modern popularity dates from 1986. Related: Empowered; empowering.
empowerment (n.): 1814, from empower + -ment.
empress (n.): mid-12c., emperice, from Old French emperesse, fem. of emperere (see emperor). Queen Victoria in 1876 became one as "Empress of India."
emprise (n.): c. 1300, "chivalrous endeavor," from Old French emprise (12c.) "enterprise, venture, adventure, undertaking," from Vulgar Latin *imprensa (source of Provençal empreza, Spanish empresa, Italian impresa), from *imprendere "to undertake," from in- (see in- (2)) + prehendere "to take" (see prehensile). Archaic in English; in French now with a literal sense "a hold, a grip."
emptiness (n.): 1530s, from empty + -ness.
emption (n.): late 15c., "purchase," from Latin emptionem (nominative emptio) "a buying, purchasing; thing bought," noun of action from past participle stem of emere "to buy" (see exempt (adj.)).
empty (adj.): c. 1200, from Old English æmettig "at leisure, not occupied; unmarried," also "containing nothing, unoccupied," from æmetta "leisure," from æ "not" + -metta, from motan "to have" (see might (n.)). The -p- is a euphonic insertion.

Sense evolution from "at leisure" to "containing nothing, unoccupied" is paralleled in several languages, such as Modern Greek adeios "empty," originally "freedom from fear," from deios "fear." "The adj. adeios must have been applied first to persons who enjoyed freedom from duties, leisure, and so were unoccupied, whence it was extended to objects that were unoccupied" [Buck]. Related: Emptier. Figurative sense of empty-nester attested by 1960.
empty (n.): "an empty thing" that was or is expected to be full, 1865, from empty (adj.). At first of barges, freight cars, mail pouches.
empty (v.): 1520s, from empty (adj.); replacing Middle English empten, from Old English geæmtigian. Related: Emptied; emptying.
empty-handed (adj.): "bringing nothing," 1610, from empty (adj.) + -handed.
empyreal (adj.): late 15c., "pertaining to the highest heaven," from Medieval Latin empyreus (see empyrean) + -al (1). Confused by early writers with imperial.
empyrean (n.): mid-14c. (as empyre), probably via Medieval Latin empyreus, from Greek empyros "fiery," from assimilated form of en (see en- (2)) + pyr "fire," from PIE root *paəwr- "fire" (see fire (n.)). As an adjective in English from early 15c. The etymological sense is "formed of pure fire or light." In ancient Greek cosmology, the highest heaven, the sphere of pure fire; later baptized with a Christian sense of "abode of God and the angels."
emu (n.): large Australian three-toed bird, 1610s, probably from Portuguese ema "crane, ostrich" (which is of unknown origin), perhaps based on a folk-etymology of a native name.
emulate (v.): 1580s, back-formation from emulation, or else from Latin aemulatus, past participle of aemulari "to rival." Related: Emulated; emulating; emulable; emulative.
emulation (n.): 1550s, from Middle French émulation (13c.) and directly from Latin aemulationem (nominative aemulatio) "rivalry, emulation, competition," noun of action from past participle stem of aemulari "to rival, strive to excel," from aemulus "striving, rivaling" (also as a noun, "a rival," fem. aemula), from Proto-Italic *aimo-, from PIE *aim-olo, suffixed form of root *aim- "copy" (see imitation).
emulator (n.): 1580s, "rival, competitor," from Latin aemulator "a zealous imitator, imitative rival," agent noun from aemulari "to rival" (see emulation). The meaning "imitative rival" in English is from 1650s.
emulgent: 1570s (adj.), 1610s (n.), from Latin emulgentem (nominative emulgens), present participle of emulgere "to milk out, drain out, exhaust" (see emulsion). Related: Emulgence.
emulous (adj.): "desirous of equaling or excelling," late 14c., from Latin aemulus "striving, rivaling," in a bad sense "envious, jealous," from aemulari "to rival" (see emulation). Related: Emulously.
emulsification (n.): 1858, noun of action from emulsify.
emulsifier (n.): 1872, agent noun from emulsify.
emulsify (v.): 1853, from Latin emuls-, past participle stem of emulgere "to milk out" (see emulsion) + -fy. Related: emulsified.
emulsion (n.): 1610s, from French émulsion (16c.), from Modern Latin emulsionem (nominative emulsio), noun of action from past participle stem of emulgere "to milk out," from assimilated form of ex- "out" (see ex-) + mulgere "to milk" (see milk (n.)). Milk is a classic instance of an emulsion, drops of one liquid dispersed throughout another.
en (n.): name of the letter "N;" in printing (1793), a space half as wide as an em.
en (prep.): French, "in; as," from Latin in (see in).
en bloc: French, literally "in a block" (see block (n.)).
en masse: French, literally "in mass" (see mass (n.1)).
en passant: French, literally "in passing," from present participle of passer "to pass" (see pass (v.)). In reference to chess, first attested 1818.
en route: 1779, French, literally "on the way" (see route (n.)).
en suite: French, literally "as part of a series or set" (see suite (n.)).
en- (1): word-forming element meaning "in; into," from French and Old French en-, from Latin in- "in, into" (see in- (2)). Typically assimilated before -p-, -b-, -m-, -l-, and -r-. Latin in- became en- in French, Spanish, Portuguese, but remained in- in Italian.

Also used with native and imported elements to form verbs from nouns and adjectives, with a sense "put in or on" (encircle), also "cause to be, make into" (endear), and used as an intensive (enclose). Spelling variants in French that were brought over into Middle English account for parallels such as ensure/insure, and most en- words in English had at one time or another a variant in in-, and vice versa.
en- (2): word-forming element meaning "near, at, in, on, within," from Greek en "in," cognate with Latin in (see in), and thus with en- (1). Typically assimilated to em- before -p-, -b-, -m-, -l-, and -r-.
enable (v.): early 15c., "to make fit;" mid-15c., "to make able to," from en- (1) "make, put in" + able. Related: Enabled; enabling. An enabling act (1684) is so called because it empowers a body or person to take certain action.
enabler (n.): 1610s, agent noun from enable.
enact (v.): early 15c., "act the part of, represent in performance," from en- (1) "make, put in" + act (v.). Meaning "decree, establish, sanction into law" is from mid-15c. Related: Enacted; enacting.
enactment (n.): 1766, "passing of a bill into law," from enact + -ment. Meaning "a law, statute" is by 1783. Earlier was enaction 1620s.
enamel (v.): early 14c., from Anglo-French enamailler (early 14c.), from en- "in" (see en- (1)) + amailler "to enamel," variant of Old French esmailler, from esmal "enamel," from Frankish *smalt, from Proto-Germanic *smaltjan "to smelt" (see smelt (v.)). Related: Enameled; enameler; enameling.
enamel (n.): early 15c., in ceramics, from enamel (v.). As "hardest part of a tooth," 1718, from a use in French émail.
enamor (v.): c. 1300, from Old French enamorer "to fall in love with; to inspire love" (12c., Modern French enamourer), from en- "in, into" (see en- (1)) + amor "love," from amare "to love" (see Amy). Since earliest appearance in English, it has been used chiefly in the past participle (enamored) and with of or with. An equivalent formation to Provençal, Spanish, Portuguese enamorar, Italian innamorare.
enamored (adj.): 1630s, past participle adjective from enamor.
enamour (v.): chiefly British English form of enamor, but also common in America and given preference of spelling in some American dictionaries; for spelling, see -or. Related: Enamoured.
encamp (v.): 1560s, "go into camp, settle in temporary quarters," from en- (1) "make, put in" + camp (n.). Related: Encamped; encamping.
encampment (n.): 1590s, "place where a camp is formed," from encamp + -ment. From 1680s as "act of forming a camp."
encapsulate (v.): 1842 (implied in encapsulated), "enclose in a capsule," from en- (1) "make, put in" + capsule + -ate (2). Figurative use by 1939. Related: Encapsulating.