experto crede Look up experto crede at Dictionary.com
Latin ("Aeneid," xi.283), "take it from one who knows;" from dative singular of expertus (see expert (adj.)) + imperative singular of credere (see credo).
expiate (v.) Look up expiate at Dictionary.com
c.1600 (OED entry has a typographical error in the earliest date), from Latin expiatus, past participle of expiare "to make amends, atone for" (see expiation). Related: Expiable (1560s); expiated; expiating.
expiation (n.) Look up expiation at Dictionary.com
early 15c., via Middle French expiation or directly from Latin expiationem (nominative expiatio) "satisfaction, atonement," noun of action from past participle stem of expiare "make amends," from ex- "completely" (see ex-) + piare "propitiate, appease," from pius "faithful, loyal, devout" (see pious).
The sacrifice of expiation is that which tendeth to appease the wrath of God. [Thomas Norton, translation of Calvin's "Institutes of Christian Religion," 1561]
expiatory (adj.) Look up expiatory at Dictionary.com
1540s, from Latin expiatorius, from expiat-, past participle stem of expiare (see expiation).
expiration (n.) Look up expiration at Dictionary.com
early 15c., "vapor, breath," from Middle French expiration, from Latin expirationem/exspirationem (nominative expiratio/exspiratio), noun of action from past participle stem of expirare/exspirare (see expire). Meaning "termination, end, close" is from 1560s.
expire (v.) Look up expire at Dictionary.com
c.1400, "to die," from Middle French expirer (12c.) "expire, elapse," from Latin expirare/exspirare "breathe out, breathe one's last, die," from ex- "out" (see ex-) + spirare "to breathe" (see spirit (n.)). "Die" is the older sense in English; that of "breathe out" is first attested 1580s. Of laws, patents, treaties, etc., mid-15c. Related: Expired; expiring.
expiry (n.) Look up expiry at Dictionary.com
"close, termination," 1752, from expire + -y (4). Meaning "dying, death" is from 1790.
explain (v.) Look up explain at Dictionary.com
early 15c., from Latin explanare "to make level, smooth out;" also "to explain, make clear" (see explanation).

Originally explane, spelling altered by influence of plain. Also see plane (v.2). In 17c., occasionally used more literally, of the unfolding of material things: Evelyn has buds that "explain into leaves" ["Sylva, or, A discourse of forest-trees, and the propagation of timber in His Majesties dominions," 1664]. Related: Explained; explaining; explains.
explanation (n.) Look up explanation at Dictionary.com
late 14c., from Latin explanationem (nominative explanatio), noun of action from past participle stem of explanare "to make plain or clear, explain," literally "make level, flatten," from ex- "out" (see ex-) + planus "flat" (see plane (n.1)).
explanatory (adj.) Look up explanatory at Dictionary.com
1610s, from or modeled on Late Latin explanatorius "having to do with an explanation," from Latin explanat-, past participle stem of explanare (see explanation).
expletive (n.) Look up expletive at Dictionary.com
1610s, originally "a word or phrase serving to fill out a sentence or metrical line," from Middle French explétif (15c.) and directly from Late Latin expletivus "serving to fill out," from explet-, past participle stem of Latin explere "fill out," from ex- "out" (see ex-) + plere "to fill" (see pleio-).

Sense of "exclamation," often in the form of a cuss word, first recorded 1815 in Sir Walter Scott, popularized by edited transcripts of Watergate tapes (mid-1970s), in which expletive deleted replaced President Nixon's salty expressions. As an adjective, from 1660s.
expletive (adj.) Look up expletive at Dictionary.com
mid-15c., from Latin expletivus (see expletive (n.)).
explicable (adj.) Look up explicable at Dictionary.com
1550s, from or on model of Latin explicabilis "capable of being unraveled, that may be explained," from explicare (see explicit). Middle English had a verb expliken "explain, interpret" (mid-15c.).
explicate (v.) Look up explicate at Dictionary.com
1530s, from Latin explicatus, past participle of explicare "unfold, unravel, explain" (see explicit). Related: Explicated; explicating.
explication (n.) Look up explication at Dictionary.com
1520s, from Middle French explication, from Latin explicationem (nominative explicatio), noun of action from past participle stem of explicare (see explicit).
explicative (adj.) Look up explicative at Dictionary.com
1640s, "having the function of explaining," from Latin explicativus, from past participle stem of explicare (see explicit). As a noun, from 1775.
explicit (adj.) Look up explicit at Dictionary.com
c.1600, from French explicite, from Latin explicitus "unobstructed," variant past participle of explicare "unfold, unravel, explain," from ex- "out" (see ex-) + plicare "to fold" (see ply (v.1)).

"Explicitus" was written at the end of medieval books, originally short for explicitus est liber "the book is unrolled." As a euphemism for "pornographic" it dates from 1971.
explicitly (adv.) Look up explicitly at Dictionary.com
1630s, from explicit + -ly (2). Opposed to implicitly.
explode (v.) Look up explode at Dictionary.com
1530s, "to reject with scorn," from Latin explodere "drive out or off by clapping, hiss off, hoot off," originally theatrical, "to drive an actor off the stage by making noise," hence "drive out, reject" (a sense surviving in an exploded theory), from ex- "out" (see ex-) + plaudere "to clap the hands, applaud," of uncertain origin. Athenian audiences were highly demonstrative. clapping and shouting approval, stamping, hissing, and hooting for disapproval. The Romans seem to have done likewise.
At the close of the performance of a comedy in the Roman theatre one of the actors dismissed the audience, with a request for their approbation, the expression being usually plaudite, vos plaudite, or vos valete et plaudite. [William Smith, "A First Latin Reading Book," 1890]
English used it to mean "drive out with violence and sudden noise" (1650s), later, "go off with a loud noise" (American English, 1790); sense of "to burst with destructive force" is first recorded 1882; of population, 1959. Related: Exploded; exploding.
exploit (n.) Look up exploit at Dictionary.com
late 14c., "outcome of an action," from Old French esploit (12c.), a very common word, used in senses of "action, deed, profit, achievement," from Latin explicitum "a thing settled, ended, or displayed," noun use of neuter of explicitus, past participle of explicare "unfold, unroll, disentangle" (see explicit).

Meaning "feat, achievement" is c.1400. Sense evolution is from "unfolding" to "bringing out" to "having advantage" to "achievement." Related: Exploits.
exploit (v.) Look up exploit at Dictionary.com
c.1400 espleiten, esploiten "to accomplish, achieve, fulfill," from Old French esploitier, espleiter, from esploit (see exploit (n.)). The sense of "use selfishly" first recorded 1838, from French, perhaps extended from use of the word with reference to mines, etc. (compare exploitation). Related: Exploited; exploiting. As an adjective form, exploitative (1882) is from French; exploitive (by 1859) appears to be a native formation.
exploitation (n.) Look up exploitation at Dictionary.com
1803, "productive working" of something, a positive word among those who used it first, though regarded as a Gallicism, from French exploitation, noun of action from exploiter (see exploit (v.)). Bad sense developed 1830s-50s, in part from influence of French socialist writings (especially Saint Simon), also perhaps influenced by U.S. anti-slavery writing; and the insulting word was hurled at activities it once had crowned as praise.
It follows from this science [conceived by Saint Simon] that the tendency of the human race is from a state of antagonism to that of an universal peaceful association -- from the dominating influence of the military spirit to that of the industriel one; from what they call l'exploitation de l'homme par l'homme to the exploitation of the globe by industry. ["Quarterly Review," April & July 1831]
exploration (n.) Look up exploration at Dictionary.com
1540s, from Middle French exploration and directly from Latin explorationem (nominative exploratio), noun of action from past participle stem of explorare (see explore).
exploratory (adj.) Look up exploratory at Dictionary.com
mid-15c., from Latin exploratorius "belonging to scouts," from explorator "scout," from explorare (see explore). Alternative explorative is from 1738.
explore (v.) Look up explore at Dictionary.com
1580s, "to investigate, examine," a back-formation from exploration, or else from Middle French explorer (16c.), from Latin explorare "investigate, search out, examine, explore," said to be originally a hunters' term meaning "set up a loud cry," from ex- "out" (see ex-) + plorare "to weep, cry."

But second element also explained as "to make to flow," from pluere "to flow." Meaning "to go to a country or place in quest of discoveries" is first attested 1610s. Related: Explored; exploring.
explorer (n.) Look up explorer at Dictionary.com
1680s, agent noun from explore. Replaced earlier exploratour (mid-15c.).
explosion (n.) Look up explosion at Dictionary.com
1620s, "action of driving out with violence and noise," from French explosion, from Latin explosionem (nominative explosio), noun of action from past participle stem of explodere "drive out by clapping" (see explode for origin and sense evolution). Meaning "going off with violence and noise" is from 1660s. Sense of "rapid increase or development" is first attested 1953.
explosive (adj.) Look up explosive at Dictionary.com
1660s, "tending to explode," from Latin explos- (past participle stem of explodere; see explosion) + -ive. As a noun, from 1874. Related: Explosives. Related: Explosively.
exponent (n.) Look up exponent at Dictionary.com
1706, from Latin exponentem (nominative exponens), present participle of exponere "put forth" (see expound). A mathematical term at first; the sense of "one who expounds" is 1812. As an adjective, from 1580s.
exponential (adj.) Look up exponential at Dictionary.com
1704, from exponent + -al (1). As a noun, from 1784. Related: Exponentially.
export (v.) Look up export at Dictionary.com
by 1610s; perhaps from late 15c., from Latin exportare "to carry out, send away," from ex- "away" (see ex-) + portare "carry" (see port (n.1)). The sense of "send out (commodities) from one country to another" is first recorded in English 1660s. The noun is from 1680s.
expose (v.) Look up expose at Dictionary.com
early 15c., "to leave without shelter or defense," from Middle French exposer "lay open, set forth" (13c.), from Latin exponere "set forth" (see expound), altered by confusion with poser "to place, lay down" (see pose (v.1)). Meaning "to exhibit openly" is from 1620s; that of "to unmask" is from 1690s. Photographic sense is from 1839. Related: Exposed; exposes; exposing.
expose (n.) Look up expose at Dictionary.com
also exposé, "display of discreditable information," 1803, initially as a French word; past participle of French exposer (see expose (v.)). Earliest use was in reference to Napoleon.
exposition (n.) Look up exposition at Dictionary.com
late 14c., "explanation, narration," from Old French esposicion (12c.), from Latin expositionem (nominative expositio) "a setting or showing forth," noun of action from past participle stem of exponere (see expound).

The meaning "public display" is first recorded 1851 in reference to the Crystal Palace Exposition in London. Abbreviation Expo is first recorded 1963, in reference to planning for the world's fair held in Montreal in 1967.
expository (adj.) Look up expository at Dictionary.com
1620s, from Medieval Latin expositorius, from expositus, past participle of exponere (see expound). Earlier in English as a noun meaning "an expository treatise, commentary" (early 15c.).
expostulate (v.) Look up expostulate at Dictionary.com
1530s, "to demand, to claim," from Latin expostulatus, past participle of expostulare "to demand urgently, remonstrate," from ex- "from" (see ex-) + postulare "to demand" (see postulate (v.)). Friendlier sense is first recorded in English 1570s. Related: Expostulated; expostulating.
expostulation (n.) Look up expostulation at Dictionary.com
1580s, from Latin expostulationem (nominative expostulatio), noun of action from past participle stem of expostulare (see expostulate).
exposure (n.) Look up exposure at Dictionary.com
c.1600, "public exhibition," from expose (v.) + -ure. Sense of "situation with regard to sun or weather" is from 1660s. Photographic sense is from 1839. Indecent exposure attested by 1825.
expound (v.) Look up expound at Dictionary.com
c.1300, from Old French espondre "expound (on), set forth, explain," from Latin exponere "put forth, explain, expose, exhibit," from ex- "forth" (see ex-) + ponere "to put, place" (see position); with intrusive -d (compare sound (n.1)). The usual Middle English form was expoune. Related: Expounded; expounding.
express (v.) Look up express at Dictionary.com
late 14c., from Old French espresser "press, squeeze out; speak one's mind" (Modern French exprimer), Medieval Latin expressare, frequentative of exprimere "represent, describe," literally "to press out" (source of Italian espresso; the sense evolution here is perhaps via an intermediary sense of something like "clay that takes under pressure takes the form of an image"), from ex- "out" (see ex-) + pressare "to press, push," from Latin premere (see press (v.1)). Related: Expressed; expresses; expressing.
express (adj.) Look up express at Dictionary.com
late 14c., from Old French expres, from Latin expressus "clearly presented," past participle of exprimere (see express (v.)). This led to the noun (first attested 1610s) meaning "special messenger." Sense of "business or system for sending money or parcels" is 1794. An express train (1841) originally ran to a certain station.
expression (n.) Look up expression at Dictionary.com
early 15c., "action of pressing out;" later (mid-15c.) "action of manifesting a feeling;" (late 15c.) "a putting into words," from Middle French expression (14c.), from Late Latin expressionem (nominative expressio), noun of action from past participle stem of exprimere (see express (v.)). Meaning "an action or creation that expresses feelings" is from 1620s. Of the face, from 1774. Occasionally the word also was used literally, for "the action of squeezing out."
expressionist Look up expressionist at Dictionary.com
an artist who seeks to portray the emotional effect of the subject, first recorded 1850 (adj.), from expression + -ist. Modern sense is from 1914, from expressionism (from 1908 as an artistic style or movement).
expressionless (adj.) Look up expressionless at Dictionary.com
1831, from expression + -less.
expressive (adj.) Look up expressive at Dictionary.com
c.1400, "tending to press out," from French expressif, from expres "clear, plain," from stem of Latin exprimere (see express (v.)). Meaning "full of expression" is from 1680s. Related: Expressively; expressiveness.
expressly (adv.) Look up expressly at Dictionary.com
late 14c., "in detail, plainly," from express + -ly (2). Meaning "for the express purpose" is c.1600.
expresso (n.) Look up expresso at Dictionary.com
variant of espresso.
expressway (n.) Look up expressway at Dictionary.com
c.1938, American English, from express (adj.) + way (n.).
expropriate (v.) Look up expropriate at Dictionary.com
1610s, back-formation from expropriation, or from earlier adjective (mid-15c.), or from Medieval Latin expropriatus, past participle of expropriare "to deprive of one's own." Related: Expropriated; expropriating.
expropriation (n.) Look up expropriation at Dictionary.com
mid-15c., "renunciation of worldly goods," from Medieval Latin expropriationem (nominative expropriatio), noun of action from Late Latin expropriare "deprive of property," from ex- "away from" (see ex-) + propriare "to appropriate" (see appropriate). Sense of "a taking of someone's property," especially for public use, is from 1848; as Weekley puts it, "Current sense of organized theft appears to have arisen among Ger. socialists."