extraordinary (adj.) Look up extraordinary at Dictionary.com
early 15c., from Latin extraordinarius "out of the common order," from extra ordinem "out of order," especially the usual order, from extra "out" (see extra-) + ordinem, accusative of ordo "order" (see order (n.)). Related: Extraordinarily.
extrapolate (v.) Look up extrapolate at Dictionary.com
1862 (in a Harvard observatory account of the comet of 1858), from extra- + ending from interpolate. Said in early references to be an expression of Sir George Airy (1801-1892), English mathematician and astronomer. Related: Extrapolated; extrapolating.
extrapolation (n.) Look up extrapolation at Dictionary.com
1867, noun of action from extrapolate by analogy of interpolation; original sense was "an inserting of intermediate terms in a mathematical series." Transferred sense of "drawing a conclusion about the future based on present tendencies" is from 1889.
extrasensory (adj.) Look up extrasensory at Dictionary.com
also extra-sensory, 1934, coined as part of extra-sensory perception in J.B. Rhine's work, from extra- + sensory.
extraterrestrial (adj.) Look up extraterrestrial at Dictionary.com
also extra-terrestrial, 1812, from extra- + terrestrial. As a noun from 1956.
extraterritoriality (n.) Look up extraterritoriality at Dictionary.com
also extra-territoriality, 1803, from extraterritorial (from extra- + territorial) + -ity.
extravagance (n.) Look up extravagance at Dictionary.com
1640s, from French extravagance, from Late Latin extravagantem (see extravagant). Specifically of wasteful spending from 1727. Extravagancy is attested from c.1600.
extravagant (adj.) Look up extravagant at Dictionary.com
late 14c., from Medieval Latin extravagantem, originally a word in Canon Law for uncodified papal decrees, present participle of extravagari "wander outside or beyond," from Latin extra "outside of" (see extra-) + vagari "wander, roam" (see vague). Extended sense of "excessive, extreme" first recorded 1590s; that of "wasteful, lavish" 1711. Related: Extravagantly.
extravaganza (n.) Look up extravaganza at Dictionary.com
1754, with reference to peculiar behavior, 1794 of a fantastic type of performance or writing, from Italian extravaganza, literally "an extravagance," from estravagante, from Medieval Latin extravagantem (see extravagant).
extravasation (n.) Look up extravasation at Dictionary.com
1670s, from Latin extra "outside" (see extra-) + form derived from vas "vessel." Related: Extravasate (1660s).
extraversion (n.) Look up extraversion at Dictionary.com
1690s, "a turning out," from Medieval Latin extraversionem, from extra "outward" (see extra-) + versionem (see version). Psychological sense is from 1915; see extraverted.
extraverted (adj.) Look up extraverted at Dictionary.com
in modern psychology, 1915, a variant of extroverted (see extrovert). Related: Extravert (n.), for which also see extrovert. There was a verb extravert in mid- to late 17c. meaning "to turn outward so as to be visible," from Latin extra "outward" + vertere "to turn."
extreme (adj.) Look up extreme at Dictionary.com
early 15c., from Old French extreme (13c.), from Latin extremus "outermost, utmost, farthest, last," superlative of exterus (see exterior).

In English as in Latin, not always felt as a superlative, hence more extreme, most extreme (which were condemned by Johnson). The noun is first recorded 1540s, originally of the end of life, compare Latin in extremis. Extreme unction preserves the sense of "last, latest" (15c.). Extremes "opposite ends of anything" is from 1550s.
extremely (adv.) Look up extremely at Dictionary.com
1530s, from extreme + -ly (2). Originally "with great severity," later more loosely, "in extreme degree" (1570s).
extremism (n.) Look up extremism at Dictionary.com
1848, from extreme + -ism.
I would remind you that extremism in the defense of liberty is no vice! And let me remind you also that moderation in the pursuit of justice is no virtue. [Barry Goldwater (1909-1998), acceptance speech as Republican candidate for President, 1963]
extremist (n.) Look up extremist at Dictionary.com
1840, from extreme + -ist.
extremities (n.) Look up extremities at Dictionary.com
"hands and feet," uttermost parts of the body, early 15c., plural of extremity. Meaning "a person's last moments" is from c.1600.
extremity (n.) Look up extremity at Dictionary.com
late 14c., from Old French estremite (13c.), from Latin extremitatem (nominative extremitas) "the end of a thing," from extremus; see extreme, the etymological sense of which is better preserved in this word.
extricable (adj.) Look up extricable at Dictionary.com
1620s, from extricate + -able. Related: Extricably.
extricate (v.) Look up extricate at Dictionary.com
1610s, from Latin extricatus, past participle of extricare "disentangle," perhaps from ex- "out of" + tricae (plural) "perplexities, hindrances," of unknown origin. Related: Extricated; extricating.
extrication (n.) Look up extrication at Dictionary.com
1640s, noun of action from extricate (v.).
extrinsic (adj.) Look up extrinsic at Dictionary.com
1540s, from French extrinsèque, from Late Latin extrinsecus (adj.), from Latin extrinsecus (adv.) "outwardly," from exter "outside" + in, suffix of locality, + secus "beside, alongside," originally "following" (related to sequi "to follow;" see sequel).
extro- Look up extro- at Dictionary.com
word-forming element meaning "outwards," a variant of extra- by influence of intro-.
extroversion (n.) Look up extroversion at Dictionary.com
mid-17c., "condition of being turned inside out," noun of action from obsolete verb extrovert (v.) "to turn inside out," from extro- + Latin vertere (see versus). Earliest as a word in mysticism; pathological sense attested from 1836; modern use in psychology attested by 1920.
extrovert (n.) Look up extrovert at Dictionary.com
1916, extravert (spelled with -o- after 1918, by influence of introvert), from German Extravert, from extra "outside" (see extra-) + Latin vertere "to turn" (see versus). With introvert, words that had been used in English by doctors and scientists in various literal senses since 1600s, but popularized in a psychological sense by Carl Jung. Related: Extroverted.
extrude (v.) Look up extrude at Dictionary.com
1560s, from Latin extrudere "to thrust out, drive away," from ex- "out" (see ex-) + trudere "to thrust" (see extrusion). Related: Extruded; extruding.
extrusion (n.) Look up extrusion at Dictionary.com
1530s, from Latin extrusionem (nominative extrusio), noun of action from past participle stem of extrudere, from ex- "out" (see ex-) + trudere "to thrust, push," from PIE *treud- "to press, push, squeeze" (see threat).
extrusive (adj.) Look up extrusive at Dictionary.com
1816, from Latin extrusus, past participle of extrudere (see extrusion) + -ive. Related: Extrusively.
exuberance (n.) Look up exuberance at Dictionary.com
1630s, from French exubérance (16c.), from Latin exuberantia "superabundance," noun of state from exuberare "be abundant, grow luxuriously" (see exuberant). Exuberancy attested from 1610s.
exuberant (adj.) Look up exuberant at Dictionary.com
mid-15c., from Middle French exubérant and directly from Latin exuberantem (nominative exuberans) "overabundance," present participle of exuberare "be abundant, grow luxuriously," from ex- "thoroughly" + uberare "be fruitful," related to uber "udder," from PIE root *eue-dh-r- (see udder). Related: Exuberantly; exuberate; exuberating.
exudation (n.) Look up exudation at Dictionary.com
1610s, from Late Latin exudationem/exsudationem, noun of action from neuter past participle of exudere/exsudere (see exude). Related: Exudate (n.).
exude (v.) Look up exude at Dictionary.com
1570s, from Latin exudare/exsudare "ooze out like sweat," from ex- "out" (see ex-) + sudare "to sweat," from sudor "sweat" (see sweat (v.)). Related: Exuded; exudes; exuding.
exult (v.) Look up exult at Dictionary.com
1560s, "to leap up;" 1590s, "to rejoice, triumph," from Middle French exulter, from Latin exultare/exsultare "leap about, leap for joy," frequentative of exsilire "to leap up," from ex- "out" (see ex-) + salire "to leap" (see salient (adj.)). The notion is of leaping or dancing for joy. Related: Exulted; exulting.
exultant (adj.) Look up exultant at Dictionary.com
1650s, from Latin exultantem/exsultantem, present participle of exultare/exsultare (see exult). Related: Exultantly.
exultation (n.) Look up exultation at Dictionary.com
early 15c., from Old French exultacion, from Latin exultationem/exsultationem, noun of action from past participle stem of exultare/exsultare, frequentative of exsilire "leap out or up" (see exult). Notion is of leaping or dancing for joy. An Old English word for it was heahbliss "high bliss."
exurb (n.) Look up exurb at Dictionary.com
"the outer, prosperous ring of the suburbs," 1955, American English, from exurban (adj.), by 1838 (it seems to have arisen in the writings of the reform movement focused on getting cemeteries out of cities), from ex- + -urb, on model of suburb. Related: Exurbanite; exurbia.
exuviae (n.) Look up exuviae at Dictionary.com
1660s, Latin, literally "that which is stripped off," hence "clothing, equipment, arms, booty, spoils," from stem of exuere, from PIE *eis- "to dress."
eye (n.) Look up eye at Dictionary.com
c.1200, from Old English ege (Mercian), eage (West Saxon), from Proto-Germanic *augon (cognates: Old Saxon aga, Old Frisian age, Old Norse auga, Swedish öga, Danish øie, Middle Dutch oghe, Dutch oog, Old High German ouga, German Auge, Gothic augo "eye"), from PIE *okw- "to see" (cognates: Sanskrit akshi "the eye, the number two," Greek opsis "a sight," Old Church Slavonic oko, Lithuanian akis, Latin oculus, Greek okkos, Tocharian ak, ek, Armenian akn).

Until late 14c. the plural was in -an, hence modern dialectal plural een, ene. The eye of a needle was in Old English; to see eye to eye is from Isa. lii:8. Eye contact attested by 1965. Eye-opener "anything that informs and enlightens" is from 1863. Have an eye on "keep under supervision" is attested from early 15c.
eye (v.) Look up eye at Dictionary.com
early 15c., "cause to see;" 1560s, "behold, observe," from eye (n.). Related: Eyed; eyeing.
eye-candy (n.) Look up eye-candy at Dictionary.com
also eye candy, "attractive woman on a TV show, etc.," by 1978, based on a metaphor also found in nose candy "cocaine" (1930).
eye-catching (adj.) Look up eye-catching at Dictionary.com
1933; earlier was noun eye-catcher (1923); see eye + catch.
eye-service (n.) Look up eye-service at Dictionary.com
"work done only under inspection or while the master is watching," 1530s, from eye (n.) + service (n.1). Related: Eye-servant.
eyeball (n.) Look up eyeball at Dictionary.com
also eye-ball, 1580s, from eye (n.) + ball (n.1). As a verb, 1901, American English slang. Related: Eyeballed; eyeballing.
eyebrow (n.) Look up eyebrow at Dictionary.com
also eye-brow, early 15c., from eye (n.) + brow (Old English eagbræw meant "eyelid").
eyelash (n.) Look up eyelash at Dictionary.com
1752, from eye (n.) + lash (n.). Related: Eyelashes.
eyelet (n.) Look up eyelet at Dictionary.com
"small hole," late 14c., oilet, from Middle French oeillet, diminutive of oeil "eye," from Latin oculus (see eye (n.)). Spelling influenced by eye.
eyelid (n.) Look up eyelid at Dictionary.com
mid-13c., from eye (n.) + lid (n.).
eyesight (n.) Look up eyesight at Dictionary.com
c.1200, from eye (n.) + sight (n.).
eyesore (n.) Look up eyesore at Dictionary.com
"something offensive to the eye," 1520s, from eye (n.) + sore (n.).
eyetooth (n.) Look up eyetooth at Dictionary.com
also eye tooth, 1570s, so called for its position immediately under or next to the eye.