exercise (n.) Look up exercise at Dictionary.com
mid-14c., "condition of being in active operation; practice for the sake of training," from Old French exercice (13c.) "exercise, execution of power; physical or spiritual exercise," from Latin exercitium "training, exercise," from exercitare, frequentative of exercere "keep busy, drive on," literally "remove restraint," from ex- "off" (see ex-) + arcere "keep away, prevent, enclose," from PIE *ark- "to hold, contain, guard" (see arcane).

Original sense may have been driving farm animals to the field to plow. Meaning "physical activity" first recorded in English late 14c.; in reference to written schoolwork from early 17c. The ending was abstracted for formations such as dancercise (1967); jazzercise (1977); and boxercise (1985).
exercise (v.) Look up exercise at Dictionary.com
late 14c., "to employ, put into active use," from exercise (n.); originally "to make use of;" also in regard to mental and spiritual training; sense of "engage in physical activity" is from 1650s. Related: Exercised; exercises; exercising.
exert (v.) Look up exert at Dictionary.com
1660s, "thrust forth, push out," from Latin exertus/exsertus, past participle of exerere/exserere "thrust out, put forth," from ex- "out" (see ex-) + serere "attach, join" (see series). Meaning "put into use" is 1680s. Related: Exerted; exerting.
exertion (n.) Look up exertion at Dictionary.com
1660s, "act of exerting," from exert + -ion. Meaning "vigorous action or effort" is from 1777.
Exeter Look up Exeter at Dictionary.com
Old English Exanceaster, Escanceaster, from Latin Isca (c.150), from Celtic river name Exe "the water" + Old English ceaster "Roman town" (see Chester).
exeunt Look up exeunt at Dictionary.com
stage direction, late 15c., from Latin, literally "they go out," third person plural present indicative of exire (see exit).
exfoliate (v.) Look up exfoliate at Dictionary.com
1610s, from Late Latin exfoliatus, past participle of exfoliare "to strip of leaves," from ex- "off" (see ex-) + folium "leaf" (see folio). Related: Exfoliated; exfoliating.
exfoliation (n.) Look up exfoliation at Dictionary.com
early 15c., noun of action from Latin exfoliare (see exfoliate).
exhalation (n.) Look up exhalation at Dictionary.com
late 14c., from Latin exhalationem (nominative exhalatio), noun of action from past participle stem of exhalare (see exhale).
exhale (v.) Look up exhale at Dictionary.com
c.1400, from Middle French exhaler (14c.), from Latin exhalare "breathe out, evaporate," from ex- "out" (see ex-) + halare "breathe." Related: Exhaled; exhaling.
exhaust (v.) Look up exhaust at Dictionary.com
1530s, "to draw off or out, to use up completely," from Latin exhaustus, past participle of exhaurire "draw off, take away, use up," from ex- "off" (see ex-) + haurire "to draw up" (as water), from PIE *aus- (3) "to draw water." Of resources, etc., from 1630s. Related: Exhausted; exhausting.
exhaust (n.) Look up exhaust at Dictionary.com
"waste gas," 1848, originally from steam engines, from exhaust (v.). In reference to internal combustion engines by 1896.
exhausted (adj.) Look up exhausted at Dictionary.com
mid-17c., "consumed, used up;" of persons, "tired out," past participle adjective from exhaust (v.). Related: Exhaustedly.
exhaustion (n.) Look up exhaustion at Dictionary.com
"fatigue," 1640s, noun of action from exhaust (v.) in sense of "drawing off" of strength.
exhaustive (adj.) Look up exhaustive at Dictionary.com
1780s, from exhaust (v.) + -ive. Related: Exhaustively; exhaustiveness.
exhibit (v.) Look up exhibit at Dictionary.com
mid-15c., from Latin exhibitus, past participle of exhibere "to hold out, display, show, present, deliver" (see exhibition). Related: Exhibited; exhibiting.
exhibit (n.) Look up exhibit at Dictionary.com
1620s, "document or object produced as evidence in court," from Latin exhibitum, neuter past participle of exhibere (see exhibition). Meaning "object displayed in a fair, museum, etc." is from 1862. Transferred use of exhibit A "important piece of evidence" is by 1906.
exhibition (n.) Look up exhibition at Dictionary.com
early 14c., from Old French exhibicion, exibicion "show, exhibition, display," from Late Latin exhibitionem (nominative exhibitio), noun of action from past participle stem of exhibere "to show, display," literally "to hold out," from ex- "out" (see ex-) + habere "to hold" (see habit (n.)).
exhibitionist (n.) Look up exhibitionist at Dictionary.com
1821, "one who takes part in an exhibition;" psychosexual sense is from 1893, in Craddock's translation of Krafft-Ebing; see exhibition + -ist. Related: Exhibitionism; exhibitionistic.
exhibitor (n.) Look up exhibitor at Dictionary.com
1650s (as exhibiter, 1590s), from Late Latin exhibitor, agent noun from past participle stem of Latin exhibere (see exhibition).
exhilarate (v.) Look up exhilarate at Dictionary.com
1530s, from Latin exhilaratus "cheerful, merry," past participle of exhilarare "gladden, cheer," from ex- "thoroughly" (see ex-) + hilarare "make cheerful," from hilarus "cheerful" (see hilarity). Related: Exhilarated; exhilarating.
exhilaration (n.) Look up exhilaration at Dictionary.com
1620s, from Late Latin exhilarationem (nominative exhilaratio), noun of action from past participle stem of exhilarare (see exhilarate).
exhort (v.) Look up exhort at Dictionary.com
c.1400, from Old French exhorer (13c.) and directly from Latin exhortari "to exhort, encourage, stimulate" (see exhortation). Related: Exhorted; exhorting.
exhortation (n.) Look up exhortation at Dictionary.com
late 14c., from Old French exhortacion and directly from Latin exhortationem (nominative exhortatio) "an exhortation, encouragement," noun of action from past participle stem of exhortari, from ex- "thoroughly" (see ex-) + hortari "encourage, urge" (see hortatory).
exhumation (n.) Look up exhumation at Dictionary.com
early 15c., from Medieval Latin exhumationem (nominative exhumatio), noun of action from past participle stem of exhumare (see exhume).
exhume (v.) Look up exhume at Dictionary.com
early 15c., from Medieval Latin exhumare "to unearth" (13c.), from Latin ex- "out of" (see ex-) + humare "bury," from humus "earth" (see chthonic). An alternative form was exhumate (1540s), taken directly from Medieval Latin. Related: Exhumed; exhuming.
exigence (n.) Look up exigence at Dictionary.com
mid-15c., from Middle French exigence or directly from Latin exigentia, from exigentem (nominative exigens), present participle of exigere (see exact (v.)).
exigency (n.) Look up exigency at Dictionary.com
1580s, from Middle French exigence, from Latin exigentia "urgency," from exigentem (nominative exigens), from exigere "to demand, require; drive out" (see exact (v.)). Related: Exigencies (1650s).
exigent (adj.) Look up exigent at Dictionary.com
1660s, "urgent," a back-formation from exigency or else from Latin exigentem (nominative exigens), present participle of exigere "to demand" (see exact (v.)).
exiguous (adj.) Look up exiguous at Dictionary.com
"scanty," 1650s, from Latin exiguus "small, petty, paltry, scanty in measure or number," from exigere (see exact (v.)).
exile (v.) Look up exile at Dictionary.com
c.1300, from Old French essillier "exile, banish, expel, drive off," from Late Latin exilare/exsilare, from Latin exilium/exsilium "banishment, exile," from exul "banished person," from ex- "away" (see ex-) + PIE root *al- "to wander" (cognates: Greek alaomai "to wander, stray, or roam about"). In ancient times folk etymology derived the second element from Latin solum "soil." Related: Exiled; exiling.
exile (n.) Look up exile at Dictionary.com
c.1300, "forced removal from one's country;" early 14c. as "a banished person;" from Old French exil, essil (12c.), from Latin exilium (see exile (v.)).
exist (v.) Look up exist at Dictionary.com
c.1600, from French exister (17c.), from Latin existere/exsistere "to step out, stand forth, emerge, appear; exist, be" (see existence). "The late appearance of the word is remarkable" [OED]. Related: Existed; existing.
existence (n.) Look up existence at Dictionary.com
late 14c., "reality," from Old French existence, from Medieval Latin existentia/exsistentia, from existentem/exsistentem (nominative existens/exsistens) "existent," present participle of Latin existere/exsistere "stand forth, appear," and, as a secondary meaning, "exist, be;" from ex- "forth" (see ex-) + sistere "cause to stand" (see assist).
existent (adj.) Look up existent at Dictionary.com
1560s, a back-formation from existence, or else from Latin existentem/exsistentem (nominative existens/exsistens), present participle of existere/exsistere (see existence).
existential (adj.) Look up existential at Dictionary.com
1690s, "pertaining to existence," from Late Latin existentialis/exsistentialis, from existentia/exsistentia (see existence). As a term in logic, from 1819; in philosophy, from 1937, tracing back to the Danish works of Kierkegaard (see existentialism). Related: Existentially.
existentialism (n.) Look up existentialism at Dictionary.com
1941, from German Existentialismus (1919), replacing Existentialforhold (1849), ultimately from Danish writer Søren Kierkegaard (1813-1855), who wrote (1846) of Existents-Forhold "condition of existence," existentielle Pathos, etc. (see existential), and whose name means, literally, "churchyard."
existentialist (adj.) Look up existentialist at Dictionary.com
1945, from French existentialiste, from existentialisme (1940); see existentialism. Related: Existentialistic.
exit (n.) Look up exit at Dictionary.com
1530s, from Latin exit "he or she goes out," third person singular present indicative of exire "go out," from ex- "out" (see ex-) + ire "to go" (see ion). Also from Latin exitus "a leaving, a going out," noun of action from exire. Originally in English a Latin stage direction (late 15c.); sense of "door for leaving" is 1786. Meaning "departure" (originally from the stage) is from 1580s. The verb is c.1600, from the noun; it ought to be left to stage directions and the clunky jargon of police reports. Related: Exited; exiting.
Those who neither know Latin nor read plays are apt to forget or not know that this is a singular verb with plural exeunt. [Fowler]
exo- Look up exo- at Dictionary.com
word-forming element meaning "outer, outside, outer part" used in scientific words (such as exoskeleton), from Greek exo "outside," related to ex "out of" (see ex-).
Exocet (n.) Look up Exocet at Dictionary.com
1970, proprietary name of a rocket-propelled short-range guided missile, trademarked 1970 by Société Nationale Industrielle Aerospatiale, from French exocet "flying fish" (16c.), from Latin exocoetus, from Greek exokoitos "sleeping fish, fish that sleeps upon the beach," from exo "outside" (see exo-) + koitos "bed."
Exodus Look up Exodus at Dictionary.com
late Old English, the second book of the Old Testament, from Latin exodus, from Greek exodos "a military expedition; a solemn procession; departure; death," literally "a going out," from ex- "out" (see ex-) + hodos "way" (see cede). General sense (with lower-case -e-) is from 1620s.
exogamy (n.) Look up exogamy at Dictionary.com
1865, Modern Latin, literally "outside marriage," from exo- + -gamy. Related: Exogamous. Apparently coined by Scottish anthropologist John Ferguson McLennan (1827-1881) in "Primitive Marriage" (see endogamy).
exogenous (adj.) Look up exogenous at Dictionary.com
1830, from Modern Latin exogenus (on model of indigenus); see exo- + -genous.
exonerate (v.) Look up exonerate at Dictionary.com
mid-15c., from Latin exoneratus, past participle of exonerare "remove a burden, discharge, unload," from ex- "off" (see ex-) + onerare "to unload; overload, oppress," from onus (genitive oneris) "burden" (see onus). Related: Exonerated; exonerating.
exoneration (n.) Look up exoneration at Dictionary.com
1630s, from Latin exonerationem (nominative exoneratio) "an unloading, lightening," noun of action from past participle stem of exonerare (see exonerate).
exorable (adj.) Look up exorable at Dictionary.com
1570s, "susceptible of being moved by entreaty" (a word much rarer than its opposite and probably used now only as a back-formation from it), from Latin exorabilis, from exorare "to persuade" (see inexorable). Related: Exorably.
exorbitance (n.) Look up exorbitance at Dictionary.com
mid-15c., from exorbitant + -ance.
exorbitant (adj.) Look up exorbitant at Dictionary.com
mid-15c., a legal term, "deviating from rule or principle, eccentric;" from Latin exorbitantem (nominative exorbitans), present participle of exorbitare "deviate, go out of the track," from ex- "out of" (see ex-) + orbita "wheel track" (see orb). Sense of "excessive, immoderate" is from 1620s; of prices, rates, etc., from 1660s. Related: Exorbitantly.
exorcise (v.) Look up exorcise at Dictionary.com
c.1400, "to invoke spirits," from Old French exorciser (14c.), from Late Latin exorcizare, from Greek exorkizein "banish an evil spirit; bind by oath" (see exorcism). Sense of "calling up evil spirits to drive them out" became dominant 16c. A rare case where -ise trumps -ize on both sides of the Atlantic, perhaps by influence of exercise. Related: Exorcised; exorcising.