asthenic (adj.) Look up asthenic at Dictionary.com
"characterized by debility, weak," 1788, from Latinized form of Greek asthenikos, asthenes "weak, without strength, feeble" (see asthenia).
asthenosphere (n.) Look up asthenosphere at Dictionary.com
layer of the Earth's upper mantle, 1914, literally "sphere of weakness" (by comparison with the lithosphere), from Greek asthenes "weak" (see asthenia) + sphere.
asthma (n.) Look up asthma at Dictionary.com
"respiratory disorder characterized by paroxysms of labored breathing and a feeling of contraction in the chest," late 14c., asma, asma, from Latin asthma, from Greek asthma "shortness of breath, a panting," from azein "breathe hard," probably related to anemos "wind," from PIE root *ane- "to breathe" (see animus). The -th- was restored in English 16c.
asthmatic (adj.) Look up asthmatic at Dictionary.com
"pertaining to or afflicted with asthma," 1540s, from Latin asthmaticus, from Greek asthmatikos, from asthma "shortness of breath" (see asthma). Noun meaning "person with asthma" is recorded from 1610s.
astigmatic (adj.) Look up astigmatic at Dictionary.com
"exhibiting astigmatism," 1849; see astigmatism + -ic.
astigmatism (n.) Look up astigmatism at Dictionary.com
"defect in the structure of the eye whereby the rays of light do not converge to a point upon the retina," 1849, coined by the Rev. William Whewell (1794-1866), English polymath, from Greek a- "without" (see a- (3)) + stigmatos genitive of stigma "a mark, spot, puncture," from PIE root *steig- "to stick; pointed" (see stick (v.)).
astir (adv.) Look up astir at Dictionary.com
"up and about," 1799, Scottish English, from phrase on the stir, or from Scottish asteer; from a- (1) + stir (see stir (v.)). Old English had astyrian, which yielded Middle English ben astired "be stirred up, excited, aroused."
astonish (v.) Look up astonish at Dictionary.com
c. 1300, astonien, "to stun, strike senseless," from Old French estoner "to stun, daze, deafen, astound," from Vulgar Latin *extonare, from Latin ex "out" (see ex-) + tonare "to thunder" (see thunder (n.)); so, literally "to leave someone thunderstruck." The modern form (influenced by English verbs in -ish, such as distinguish, diminish) is attested from 1520s. The meaning "amaze, shock with wonder" is from 1610s.
No wonder is thogh that she were astoned [Chaucer, "Clerk's Tale"]
Related: Astonished; astonishing.
astonishing (adj.) Look up astonishing at Dictionary.com
"causing wonder or amazement," 1620s, present-participle adjective from astonish. Related: Astonishingly.
astonishment (n.) Look up astonishment at Dictionary.com
1590s, state of being amazed or shocked with wonder;" see astonish + -ment. Earlier it meant "paralysis" (1570s).
astound (v.) Look up astound at Dictionary.com
mid-15c., from Middle English astouned, astoned (c. 1300), past participle of astonen, astonien "to stun" (see astonish), with more of the original sense of Vulgar Latin *extonare. The unusual form is perhaps because the past participle was so much more common it came to be taken for the infinitive, or/and by the same pattern which produced round (v.) from round (adj.), or by the intrusion of an unetymological -d as in sound (n.1). Related: Astounded; astounding.
astounding (adj.) Look up astounding at Dictionary.com
"stunning," 1580s, present-participle adjective from astound (v.). Related: Astoundingly.
astral (adj.) Look up astral at Dictionary.com
c. 1600, "pertaining to the stars," from Late Latin astralis, from Latin astrum "star," from Greek astron "a star" (from PIE root *ster- (2) "star"). Meaning "pertaining to supersensible substances" is from 1690s, popularized late 19c. in Theosophy.
astray (adv.) Look up astray at Dictionary.com
c. 1300, astraied "away from home; lost, wandering," borrowed and partially nativized from Old French estraie, past participle of estraier "astray, riderless (of a horse), lost," literally "on stray" (see stray (v.)).
astriction (n.) Look up astriction at Dictionary.com
"act of binding close or constricting," especially contraction by applications, 1560s, from Latin astrictionem (nominative astrictio), noun of action from past participle stem of astringere "to bind fast, tighten, contract," from assimilated form of ad "to" (see ad-) + stringere "draw tight" (see strain (v.)). Related: Astrictive (1550s). As verbs, astrict is from 1510s; astringe from 1520s.
Astrid Look up Astrid at Dictionary.com
fem. proper name, from Norse; it is cognate with Old High German Ansitruda, from ansi "god" (see Aesir) + trut "beloved, dear."
astride (adv.) Look up astride at Dictionary.com
"with one leg on each side," 1660s, from a- (1) "on" + stride (n.).
astringent (adj.) Look up astringent at Dictionary.com
1540s, "binding, contracting," from Latin astringentum (nominative astringens), present participle of astringere "to bind fast, tighten, contract," from assimilated form of ad "to" (see ad-) + stringere "draw tight" (see strain (v.)). Related: Astringently; astringency. As a noun from 1620s, "an astringent substance, something which contracts tissues and thereby checks discharge of blood."
astro- Look up astro- at Dictionary.com
element active in English word formation from mid-18c. and meaning "star or celestial body; outer space," from Greek astro-, stem and comb. form of astron "star," which is related to aster "star," from PIE root *ster- (2) "star." In ancient Greek, aster typically was "a star" and astron mostly in plural, "the stars." In singular it mostly meant "Sirius" (the brightest star).
astrobiology (n.) Look up astrobiology at Dictionary.com
1903, from French astrobiologie; see astro- "star" + biology. Related: Astrobiological; astrobiologist.
astrobleme (n.) Look up astrobleme at Dictionary.com
"crypto-explosion structure on Earth caused by meteorite or asteroid impact," 1961, literally "star-wound," from astro- "star" + Greek bleme "throw of a missile; wound caused by a missile," from ballein "to throw" (see ballistics). Coined by U.S. geologist Robert S. Dietz (1914-1995).
astrognosy (n.) Look up astrognosy at Dictionary.com
"knowledge of the fixed stars, their names, magnitudes, etc.," 1835, from astro- "star" + -gnosy, from Greek gnosis "a knowing, knowledge," from PIE root *gno- "to know."
astrography (n.) Look up astrography at Dictionary.com
"the mapping of the fixed stars," 1740, from astro- + -graphy. Related: Astrographic.
astroid (adj.) Look up astroid at Dictionary.com
"star-shaped," 1909, from Greek astroeides, from astron "star" (from PIE root *ster- (2) "star") + -oeides (see -oid). Earlier as a noun (1897).
astrolabe (n.) Look up astrolabe at Dictionary.com
"instrument for measuring the altitude of the sun and stars," mid-14c., from Old French astrelabe, from Medieval Latin astrolabium, from Greek astrolabos (organon) "star-taking (instrument)," from astron "star" (from PIE root *ster- (2) "star") + lambanien "to take" (see lemma).
astrolatry (n.) Look up astrolatry at Dictionary.com
"worship of heavenly bodies," 1670s; see astro- "star" + -latry "worship."
astrologer (n.) Look up astrologer at Dictionary.com
late 14c., "an observer of the stars," from astrology + -er (1). It drove out French import astrologein, which, had it survived, probably would have yielded *astrologian, as in Chaucer's "The wise Astrologen." Also in Middle English in reference to cocks as announcers of sunrise.

Narrowed meaning "one who professes to determine the influence of planets on persons and events" is from c. 1600, however during the early Modern English period when astrologer and astronomer began to be differentiated, "the relation between them was at first the converse of the present usage" [OED]. Shakespeare used astronomer where we would write astrologer.
astrological (adj.) Look up astrological at Dictionary.com
"pertaining to astrology," 1590s; see astrology + -ical. Related: Astrologically.
astrology (n.) Look up astrology at Dictionary.com
late 14c., "calculation and foretelling based on observation of heavenly bodies," from Latin astrologia "astronomy, the science of the heavenly bodies," from Greek astrologia "astronomy," literally "a telling of the stars," from astron "star" (from PIE root *ster- (2) "star") + -logia "treating of" (see -logy).

Originally identical with astronomy and including scientific observation and description. The special sense of "astronomy applied to prediction of events" was divided into natural astrology "the calculation and foretelling of natural phenomenon" (tides, eclipses, dates of Church festivals, etc.), and judicial astrology "the art of judging occult influences of stars and planets on human affairs." Differentiation between astrology and astronomy began late 1400s and by 17c. this word was limited to the sense of "reading influences of the stars and their effects on human destiny."
astromancy (n.) Look up astromancy at Dictionary.com
"astrology, art of judging occult influences of stars and planets on human affairs," 1650s; see astro- + -mancy.
astronaut (n.) Look up astronaut at Dictionary.com
"space-traveler," 1929 in scientific speculation, popularized from 1961 by U.S. space program, from astro- "star" + nautes "sailor," from PIE root *nāu- (2) "boat" (see naval). French astronautique (adj.) had been coined 1927 by "J.H. Rosny," pen name of Belgian-born science fiction writer Joseph Henri Honoré Boex (1856-1940) on model of aéronautique, and Astronaut was used in 1880 as the name of a fictional spaceship by English writer Percy Greg (1836-1889) in "Across the Zodiac."
astronautics (n.) Look up astronautics at Dictionary.com
"the art of traveling in outer space," 1929; see astronaut + -ics.
astronomer (n.) Look up astronomer at Dictionary.com
"one versed in the laws of the heavenly bodies," late 14c., from astronomy (q.v.) + -er (1). It replaced French import astronomyen (c. 1300), which, had it survived, probably would have yielded *astronomian. For sense differentiation, see astrologer.
astronomical (adj.) Look up astronomical at Dictionary.com
1550s, "pertaining to astronomy," from astronomy + -ical. Popular meaning "immense, concerning very large figures" (as sizes and distances in astronomy) is attested from 1899. Astronomical unit (abbreviation A.U.) "mean distance from the Earth to the Sun," used as a unit of measure of distance in space, is from 1909. Related: Astronomically.
astronomy (n.) Look up astronomy at Dictionary.com
c. 1200, "astronomy, astrology, scientific or occult study of heavenly bodies," from Old French astrenomie "astronomy, astrology," from Latin astronomia, from Greek astronomia, abstract noun from astronomos, literally "star-regulating," from astron "star" (from PIE root *ster- (2) "star") + nomos "arranging, regulating; rule, law" from PIE root *nem- "to divide, distribute, allot" (see nemesis). Perhaps originally with reference to mapping the constellations or movements of planets.
Þer wes moni god clarc to lokien in þan leofte, to lokien i þan steorren nehʒe and feorren. þe craft is ihate Astronomie. [Layamon, "The Brut," c. 1200]
In English, it is earlier than astrology and originally included the senses now distributed over both words; the gradual differentiation happened 16c.-17c. In Latin and later Greek, astronomia tended to be more scientific than astrologia.
astrophotography (n.) Look up astrophotography at Dictionary.com
"application of photography to the stars, sun, planets, etc.," 1858, from astro- + photography.
astrophysicist (n.) Look up astrophysicist at Dictionary.com
"expert in the physics of heavenly bodies," also astro-physicist, 1869, from astro- + physicist. Related: Astrophysics (1877); astrophysical.
AstroTurf (n.) Look up AstroTurf at Dictionary.com
1966, proprietary name for a kind of artificial grass, so called because it was used first in the Houston, Texas, Astrodome, indoor sports stadium. See astro- + turf. Houston was the control center of the U.S. space program.
astute (adj.) Look up astute at Dictionary.com
"keen in discernment and careful of one's self-interest," 1610s, from Latin astutus "crafty, wary, shrewd; sagacious, expert," from astus "cunning, cleverness, adroitness," which is of uncertain origin. The Romans considered it to be from Greek asty "town," borrowed into Latin and implying city sophistication (see asteism). Related: Astutely; astuteness.

An alternative form is astucious (1823), from French astucieux, from Latin astutia "astuteness." Also formerly astucity.
Astyanax Look up Astyanax at Dictionary.com
son of Hector and Andromache ("Iliad"), Greek, literally "lord of the city," from asty "city" (see asteism) + anax "chief, lord, master." Also the epithet of certain gods.
asunder (adv.) Look up asunder at Dictionary.com
"into a position apart, separate, into separate parts," mid-12c., contraction of Old English on sundran (see a- (1) + sunder). Middle English used to know asunder for "distinguish, tell apart."
asylum (n.) Look up asylum at Dictionary.com
early 15c., earlier asile (late 14c.), "place of refuge, sanctuary," from Latin asylum "sanctuary," from Greek asylon "refuge, fenced territory," noun use of neuter of asylos "inviolable, safe from violence," especially of persons seeking protection, from a- "without" (see a- (3)) + syle "right of seizure," which is of unknown etymology.

Literally, "an inviolable place." Formerly a place where criminals and debtors sought shelter from justice and from which they could not be taken without sacrilege. General sense of "safe or secure place" is from 1640s; abstract sense "inviolable shelter, protection from pursuit or arrest" is from 1712. Meaning "benevolent institution to shelter some class of persons suffering social, mental, or bodily defects" is from 1773, originally of female orphans.
asymmetrical (adj.) Look up asymmetrical at Dictionary.com
1680s; see asymmetry + -ical. Other forms that have served as an adjective based on asymmetry are asymmetral (1620s), asymmetrous (1660s), and asymmetric (1839); only the last seems to have any general currency. Related: Asymmetrically.
asymmetry (n.) Look up asymmetry at Dictionary.com
1650s, "want of symmetry or proportion," from Greek asymmetria "want of proportion or harmony," noun of quality from asymmetros "having no common measure; disproportionate, unsymmetrical," from a- "not" (see a- (3)) + symmetros "commensurable" (see symmetry).
asymptomatic (adj.) Look up asymptomatic at Dictionary.com
"without symptoms," 1856, from a- (3) "not, without" + symptomatic.
asymptote (n.) Look up asymptote at Dictionary.com
"straight line continually approaching but never meeting a curve," 1650s, from Greek asymptotos "not falling together," from a- "not" (see a- (3)) + assimilated form of syn "with" (see syn-) + ptotos "fallen," verbal adjective from piptein "to fall," from PIE root *pet- "to rush; to fly" (see petition (n.)). Related: Asymptosy.
asymptotic (adj.) Look up asymptotic at Dictionary.com
"having the characteristics of an asymptote," 1670s, see asymptote + -ic. Related: Asymptotical; asymptotically.
asynchronous (adj.) Look up asynchronous at Dictionary.com
"not coinciding in time," 1748, from a- (3) "not, without" + synchronous "existing or happening at the same time." Related: Asynchronicity; asynchronism (1850).
asyndetic (adj.) Look up asyndetic at Dictionary.com
"characterized by asyndeton," 1823; see asyndeton + -ic.
asyndeton (n.) Look up asyndeton at Dictionary.com
"figure of speech consisting of omission of conjunctions," 1580s, from Latin, from Greek asyndeton, neuter of asyndetos "unconnected," from a- "not, without" (see a- (3)) + syndetos, from syndein "to bind together," from syn- "together" (see syn-) + dein "to bind," related to desmos "band," from PIE root *dē- "to bind" (see diadem).
"I pitied thee, Took pains to make thee speak, taught thee each hour One thing or other." ["The Tempest"]