expediently (adv.) Look up expediently at Dictionary.com
late 14c., from expedient (adj.) + -ly (2).
expedite (v.) Look up expedite at Dictionary.com
c.1500 (implied in past participle expedit "accomplished"), from Latin expeditus, past participle of expedire "extricate, disengage, liberate; procure, make ready, put in order, make fit, prepare; explain, make clear," literally "free the feet from fetters," hence to liberate from difficulties, from ex- "out" (see ex-) + *pedis "fetter, chain for the feet," related to pes (genitive pedis) "foot" (see foot (n.)). Compare Greek pede "fetter." Related: Expedited; expediting.
expedition (n.) Look up expedition at Dictionary.com
early 15c., "military campaign; the act of rapidly setting forth," from Old French expedicion "an expediting, implementation; expedition, mission" (13c.) and directly from Latin expeditionem (nominative expeditio) "an enterprise against an enemy, a military campaign," noun of action from past participle stem of expedire "make ready, prepare" (see expedite). Meaning "journey for some purpose" is from 1590s. Sense by 1690s also included the body of persons on such a journey.
expeditionary (adj.) Look up expeditionary at Dictionary.com
1803, from expedition + -ary.
expeditious (adj.) Look up expeditious at Dictionary.com
late 15c., expedycius "useful, fitting," from Latin expeditus "disengaged, ready, convenient, prompt; unfettered, unencumbered," past participle of expedire (see expedite). Meaning "speedy, speedily accomplished" is from 1590s. Related: Expeditiously; expeditiousness.
expel (v.) Look up expel at Dictionary.com
late 14c., "cast out," from Latin expellere "drive out, drive away," from ex- "out" (see ex-) + pellere "to drive" (see pulse (n.1)). Specific meaning "to eject from a school" is first recorded 1640s. Related: Expelled; expelling.
expellee (n.) Look up expellee at Dictionary.com
1888, from expel + -ee.
expend (v.) Look up expend at Dictionary.com
early 15c., from Latin expendere "pay out, weigh out money," from ex- "out" (see ex-) + pendere "to pay, weigh" (see pendant). Related: Expended; expending.
expendable (adj.) Look up expendable at Dictionary.com
1805, from expend + -able.
expenditure (n.) Look up expenditure at Dictionary.com
1769, "act of expending," from Medieval Latin expenditus, irregular past participle of Latin expendere "to weigh out; to pay out" (see expend) + -ure. Meaning "that which is expended" is from 1791. Related: Expenditures.
expense (n.) Look up expense at Dictionary.com
also formerly expence, late 14c., "action of spending or giving away, a laying out or expending," also "funds provided for expenses, expense money; damage or loss from any cause," from Anglo-French expense, Old French espense "money provided for expenses," from Late Latin expensa "disbursement, outlay, expense," noun use of neuter plural past participle of Latin expendere "to weigh out money, to pay down" (see expend).

Latin spensa also yielded Medieval Latin spe(n)sa, the sense of which specialized to "outlay for provisions," then "provisions, food" before it was borrowed into Old High German as spisa and became the root of German Speise "food," now mostly meaning prepared food, and speisen "to eat." Expense account is from 1872.
expense (v.) Look up expense at Dictionary.com
1909, from expense (n.). Related: Expensed; expensing.
expenses (n.) Look up expenses at Dictionary.com
"charges incurred in the discharge of duty," late 14c. See expense (n.).
expensive (adj.) Look up expensive at Dictionary.com
1620s, "given to profuse expenditure," from expense (n.) + -ive. Meaning "costly, requiring profuse expenditure" is from 1630s. Earlier was expenseful (c.1600). Expenseless was in use mid-17c.-18c., but there seems now nothing notable to which it applies, and the dictionaries label it "obsolete." Related: Expensively; expensiveness.
experience (n.) Look up experience at Dictionary.com
late 14c., "observation as the source of knowledge; actual observation; an event which has affected one," from Old French esperience "experiment, proof, experience" (13c.), from Latin experientia "a trial, proof, experiment; knowledge gained by repeated trials," from experientem (nominative experiens) "experienced, enterprising, active, industrious," present participle of experiri "to try, test," from ex- "out of" (see ex-) + peritus "experienced, tested," from PIE root *per- (3) "to lead, pass over" (see peril). Meaning "state of having done something and gotten handy at it" is from late 15c.
experience (v.) Look up experience at Dictionary.com
1530s, "to test, try, learn by practical trial or proof;" see experience (n.). Sense of "feel, undergo" first recorded 1580s. Related: Experienced; experiences; experiencing.
experienced (adj.) Look up experienced at Dictionary.com
"having experience, taught by practice, skillful through doing," 1570s, past participle adjective from experience (v.).
experiential (adj.) Look up experiential at Dictionary.com
1640s (implied in experientially), from Latin experientia "knowledge gained by testing or trials" (see experience (n.)) + -al (1).
experiment (n.) Look up experiment at Dictionary.com
mid-14c., "action of observing or testing; an observation, test, or trial;" also "piece of evidence or empirical proof; feat of magic or sorcery," from Old French esperment "practical knowledge, cunning; enchantment, magic spell; trial, proof, example; lesson, sign, indication," from Latin experimentum "a trial, test, proof, experiment," noun of action from experiri "to test, try" (see experience (n.)).
experiment (v.) Look up experiment at Dictionary.com
late 15c., from experiment (n.). Intransitive sense by 1787. Related: Experimented; experimenting.
experimental (adj.) Look up experimental at Dictionary.com
mid 15c., "having experience," from experiment (n.) + -al (1). Meaning "based on experiment" is from 1560s. Meaning "for the sake of experiment" is from 1792.
experimentation (n.) Look up experimentation at Dictionary.com
1670s, noun of action from experiment (v.).
expert (adj.) Look up expert at Dictionary.com
late 14c., "having had experience; skillful," from Old French expert, espert "experienced, practiced, skilled" and directly from Latin expertus (contracted from *experitus), "tried, proved, known by experience," past participle of experiri "to try, test" (see experience). The adjective tends to be accented on the second syllable, the noun on the first. Related: Expertly; expertness.
expert (n.) Look up expert at Dictionary.com
early 15c., "person wise through experience," from expert (adj.). The word reappeared 1825 in the legal sense, "person who, by virtue of special acquired knowledge or experience on a subject, presumably not within the knowledge of men generally, may testify in a court of justice to matters of opinion thereon, as distinguished from ordinary witnesses, who can in general testify only to facts" [Century Dictionary].
expertise (n.) Look up expertise at Dictionary.com
"quality or state of being an expert," 1868, from French expertise (16c.) "expert appraisal, expert's report," from expert (see expert). Earlier and more English was expertness (c.1600).
experto crede Look up experto crede at Dictionary.com
Latin, "take it from one who knows" ("Aeneid," xi.283); dative singular of expertus (see expert (adj.)) + imperative singular of credere (see credo).
expiate (v.) Look up expiate at Dictionary.com
c.1600 (OED 2nd ed. print 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 for, atone for; purge by sacrifice, make good," 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 Late Latin expiatorius, from expiat-, past participle stem of Latin expiare "make amends" (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) "a breathing out, exhalation," noun of action from past participle stem of expirare/exspirare "breathe out; breathe one's last" (see expire). Meaning "termination, end, close" is from 1560s.
expire (v.) Look up expire at Dictionary.com
c.1400, "to die," from Old French expirer "expire, elapse" (12c.), from Latin expirare/exspirare "breathe out, blow out, exhale; breathe one's last, die," hence, figuratively, "expire, come to an end, cease," 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. In 17c. also transitive. 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 explain, make clear, make plain" (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. To explain (something) away is from 1709.
explainable (adj.) Look up explainable at Dictionary.com
c.1600, from explain + -able.
explanation (n.) Look up explanation at Dictionary.com
late 14c., from Latin explanationem (nominative explanatio) "an explanation, interpretation," 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 "make plain or clear" (see explanation).
expletive (n.) Look up expletive at Dictionary.com
1610s, "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, fill up, glut," from ex- "out" (see ex-) + plere "to fill" (see pleio-).

Sense of "an exclamation," especially "a curse word, an oath," 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., in grammar, "correlative," from Latin expletivus "serving to fill out" (see expletive (n.)).
explicable (adj.) Look up explicable at Dictionary.com
1550s, from or modeled on Latin explicabilis "capable of being unraveled, that may be explained," from explicare "unfold; explain" (see explicit). Middle English had a verb expliken "explain, interpret" (mid-15c.).
explicate (v.) Look up explicate at Dictionary.com
"give a detailed account of," 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 "unfold; explain" (see explicit).
explicative (adj.) Look up explicative at Dictionary.com
1640s, "having the function of explaining," from Latin explicativus, from explicat-, past participle stem of explicare "unfold; explain" (see explicit). As a noun, from 1775.
explicit (adj.) Look up explicit at Dictionary.com
1610s, "open to the understanding, not obscure or ambiguous," 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)). As a euphemism for "pornographic" it dates from 1971. Related: Explicitness. "Explicitus" was written at the end of medieval books, originally short for explicitus est liber "the book is unrolled."
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 (transitive), "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, destroy the repute of" (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 "cause to burst suddenly and noisily" (1794). Intransitive sense of "go off with a loud noise" is from 1790, American English; figurative sense of "to burst with destructive force" is by 1882; that of "burst into sudden activity" is from 1817; of population by 1959. Related: Exploded; exploding.
exploit (n.) Look up exploit at Dictionary.com
late 14c., "outcome of an action," from Old French esploit "a carrying out; achievement, result; gain, advantage" (12c., Modern French exploit), 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 "carry out, perform, accomplish," from esploit (see exploit (n.)). The sense of "use selfishly" first recorded 1838, from a sense development in French perhaps from use of the word with reference to mines, etc. (compare exploitation). Related: Exploited; exploiting.
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 use of the word in U.S. anti-slavery writing; and exploitation was hurled in insult 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]
exploitative (adj.) Look up exploitative at Dictionary.com
1882, from French exploitatif, from exploit (see exploit (n.)). Alternative exploitive (by 1859) appears to be a native formation from exploit + -ive.
exploration (n.) Look up exploration at Dictionary.com
1540s, from Middle French exploration and directly from Latin explorationem (nominative exploratio) "an examination," noun of action from past participle stem of explorare "investigate, examine" (see explore). Alternative explorement is from 1640s.