exorcism (n.) Look up exorcism at Dictionary.com
early 15c., "a calling up or driving out of evil spirits," from Late Latin exorcismus, from Greek exorkismos, from exorkizein "exorcize, bind by oath," from ex "out of" (see ex-) + horkizein "cause to swear," from horkos "oath." Earlier in the same sense was exorcization (late 14c.).
exorcist (n.) Look up exorcist at Dictionary.com
"one who drives out evil spirits," late 14c., from Late Latin exorcista, from Ecclesiastical Greek exorkistes "an exorcist," from exorkizein (see exorcism).
exoskeleton (n.) Look up exoskeleton at Dictionary.com
1847, from exo- + skeleton. Introduced by English anatomist Sir Richard Owen (1804-1892).
exoteric (adj.) Look up exoteric at Dictionary.com
1650s, from Late Latin exotericus, from Greek exoterikos, from exotero, comparative of exo (see exo-).
exothermic (adj.) Look up exothermic at Dictionary.com
1879, from French exothermique (1879), from exo- + thermique, ultimately from Greek therme "heat" (see thermal).
exotic (adj.) Look up exotic at Dictionary.com
1590s, "belonging to another country," from Middle French exotique (16c.) and directly from Latin exoticus, from Greek exotikos "foreign," literally "from the outside," from exo "outside" (see exo-). Sense of "unusual, strange" first recorded in English 1620s, from notion of "alien, outlandish." In reference to strip-teasers and dancing girls, it is first attested by 1942, American English.
Exotic dancer in the nightclub trade means a girl who goes through a few motions while wearing as few clothes as the cops will allow in the city where she is working ... ["Life," May 5, 1947]
As a noun from 1640s.
exoticism (n.) Look up exoticism at Dictionary.com
1827, from exotic + -ism.
expand (v) Look up expand at Dictionary.com
early 15c., "spread out, spread flat," from Anglo-French espaundre, Middle French espandre and directly from Latin expandere "to spread out, unfold, expand," from ex- "out" (see ex-) + pandere "to spread, stretch" (see pace (n.)). Sense of "grow larger" first recorded 1640s. Related: Expanded; expanding.
expanse (n.) Look up expanse at Dictionary.com
1660s, from Latin expansum, noun use of neuter of expansus, past participle of expandere (see expand).
expansion (n.) Look up expansion at Dictionary.com
1610s, "anything spread out;" 1640s, "act of expanding," from French expansion, from Late Latin expansionem (nominative expansio) "a spreading out," noun of action from past participle stem of Latin expandere (see expand).
expansionist (n.) Look up expansionist at Dictionary.com
"one who advocates the expansion of the territory of his nation," 1864, from expansion + -ist. Related: Expansionism.
expansive (adj.) Look up expansive at Dictionary.com
1650s, "tending to expand," from Latin expans-, past participle stem of expandere (see expand) + -ive. Related: Expansively; expansiveness.
expat (n.) Look up expat at Dictionary.com
1962, shortening of expatriate (n.).
expatiate (v.) Look up expatiate at Dictionary.com
1530s, "walk about, roam freely," from Latin expatiatus/exspatiatus, past participle of expatiari/exspatiari "wander, digress," from ex- "out" (see ex-) + spatiari "to walk, spread out," from spatium (see space). Meaning "talk or write at length" is 1610s. Related: Expatiated; expatiating.
expatriate (v.) Look up expatriate at Dictionary.com
1768, from French expatrier "banish" (14c.), from ex- "out of" (see ex-) + patrie "native land," from Latin patria "one's native country," from pater (genitive patris) "father" (see father (n.); also compare patriot). Related: Expatriated; expatriating. The noun is from 1818, "one who has been banished;" main modern sense of "one who chooses to live abroad" is 1902.
expatriation (n.) Look up expatriation at Dictionary.com
1816, from French expatriation, noun of action from expatrier (see expatriate).
expect (v.) Look up expect at Dictionary.com
1550s, "wait, defer action," from Latin expectare/exspectare "await, look out for, desire, hope," from ex- "thoroughly" (see ex-) + spectare "to look," frequentative of specere "to look at" (see scope (n.1)).

Figurative sense of "anticipate, look forward to" developed in Latin, attested in English from c.1600. Used since 1817 as a euphemism for "be pregnant." Related: Expected; expecting.
expectancy (n.) Look up expectancy at Dictionary.com
1590s, from Latin expectantia (see expectant) + -ancy.
expectant (adj.) Look up expectant at Dictionary.com
late 14c., from Old French expectant or directly from Latin expectantem/exspectantem (nominative expectans/exspectans), present participle of expectare/exspectare (see expect). Related: Expectantly. As a noun, from 1620s.
expectation (n.) Look up expectation at Dictionary.com
1530s, from Middle French expectation (14c.) or directly from Latin expectationem/exspectationem (nominative expectatio/exspectatio) "anticipation, an awaiting," noun of action from past participle stem of expectare/exspectare (see expect). Related: Expectations.
expectorant (n.) Look up expectorant at Dictionary.com
1782, from Latin expectorantem (nominative expectorans), present participle of expectorare (see expectorate). From 1811 as an adjective.
expectorate (v.) Look up expectorate at Dictionary.com
c.1600, "to clear out the chest or lungs," from Latin expectoratus, past participle of expectorare "scorn, expel from the mind," literally "make a clean breast," from ex- "out" (see ex-) + pectus (genitive pectoris) "breast" (see pectoral (adj.)). Use as a euphemism for "spit" is first recorded 1827. Original sense in expectorant. Related: Expectorated; expectorating.
expectoration (n.) Look up expectoration at Dictionary.com
1670s, noun of action from expectorate.
expediate (v.) Look up expediate at Dictionary.com
a 17c. error for expedite that has gotten into the dictionaries.
expedience (n.) Look up expedience at Dictionary.com
mid-15c., "advantage, benefit," from Old French expedience, from Late Latin expedientia, from expedientem (see expedient). Related: Expediency (1610s).
expedient (adj.) Look up expedient at Dictionary.com
late 14c., "advantageous, fit, proper," from Old French expedient (14c.) or directly from Latin expedientem (nominative expediens) "beneficial," present participle of expedire "make fit or ready, prepare" (see expedite). The noun meaning "a device adopted in an exigency, a resource" is from 1650s. Related: Expediential; expedientially (both 19c.)
expediently (adv.) Look up expediently at Dictionary.com
late 14c., from expedient (adj.) + -ly (2).
expedite (v.) Look up expedite at Dictionary.com
late 15c. (implied in past participle expedit), from Latin expeditus, past participle of expedire "extricate, disengage, liberate; procure, make ready, make fit, prepare," literally "free the feet from fetters," hence "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 Middle French expédition (13c.) and directly from Latin expeditionem (nominative expeditio), noun of action from past participle stem of expedire (see expedite). Meaning "journey for some purpose" is from 1590s. Sense by 1690s also included the body of persons on such a journey. Related: Expeditionary.
expeditious (adj.) Look up expeditious at Dictionary.com
late 15c., expedycius "useful, fitting," from Latin expeditus "disengaged, ready, prompt," past participle of expidere (see expedite). Meaning "speedy" is from 1590s. Related: Expeditiously; expeditiousness.
expel (v.) Look up expel at Dictionary.com
late 14c., from Latin expellere "drive out," from ex- "out" (see ex-) + pellere "to drive" (see pulse (n.1)). 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, from Medieval Latin expenditus, irregular past participle of expendere (see expend) + -ure. Related: Expenditures.
expense (n.) Look up expense at Dictionary.com
late 14c., 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, whose sense specialized to "outlay for provisions," then "provisions, food," which was borrowed into Old High German as spisa and is the root of German Speise "food," now mostly meaning prepared food, and speisen "to eat."
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" 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."
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 (13c.) "experiment, proof, experience," from Latin experientia "knowledge gained by repeated trials," from experientem (nominative experiens), present participle of experiri "to try, test," from ex- "out of" (see ex-) + peritus "experienced, tested," from PIE root *per- "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;" see experience (n.). Sense of "feel, undergo" first recorded 1580s. Related: Experienced; experiences; experiencing.
experienced (adj.) Look up experienced at Dictionary.com
"having experience; skillful through experience," 1570s, past participle adjective from experience (v.).
experiential (adj.) Look up experiential at Dictionary.com
1640s (implied in experientially), from Latin experientia (see experience (n.)) + -al (1).
experiment (n.) Look up experiment at Dictionary.com
mid-14c., from Old French esperment "practical knowledge, cunning, enchantment; trial, proof, example, lesson," 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.). Related: Experimented; experimenting.
experimental (adj.) Look up experimental at Dictionary.com
mid 15c., "having experience," from experiment (n.) + -al (1). Meaning "based on experience" is from 1560s. Meaning "for the sake of experiment" is from 1792 (as in Experimental farm).
experimentation (n.) Look up experimentation at Dictionary.com
1670s; see experiment (v.) + -ation.
expert (adj.) Look up expert at Dictionary.com
late 14c., from Old French expert and directly from Latin expertus, past participle of experiri "to try, test" (see experience). The noun sense of "person wise through experience" existed 15c., reappeared 1825. Related: Expertly.
expertise (n.) Look up expertise at Dictionary.com
1868, from French expertise (16c.) "expert appraisal, expert's report," from expert (see expert). Earlier in same sense was expertness (c.1600).
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).