Online Etymology Dictionary

asthenia (n.): "weakness," 1802, Modern Latin, from Greek asthenia, from asthenes "weak, without strength, feeble," from a-, privative prefix (see a- (3)), + sthenos "strength," of uncertain origin.
asthenic (adj.): 1789, from Modern Latin, from Greek asthenikos, from asthenes (see asthenia).
asthenosphere (n.): layer of the Earth's upper mantle, 1914, from Greek asthenos (see asthenia) + sphere.
asthma (n.): late 14c. asma, asma, from Latin asthma, from Greek asthma "short breath, a panting," from azein "breathe hard," probably related to anemos "wind." The -th- was restored in English 16c.
asthmatic (adj.): 1540s, from Latin asthmaticus, from Greek asthmatikos, from asthma (see asthma). Noun meaning "person with asthma" is recorded from 1610s.
astigmatic (adj.): 1849; see astigmatism + -ic.
astigmatism (n.): 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" (see stick (v.)).
astir (adv.): "up and about," 1823, from phrase on the stir, or from Scottish asteer; from stir. Old English had astyrian, which yielded Middle English ben astired "be stirred up, excited, aroused."
astonish (v.): c.1300, astonien, from Old French estoner "to stun, daze, deafen, astound," from Vulgar Latin *extonare, from Latin ex- "out" + tonare "to thunder" (see thunder); so, literally "to leave someone thunderstruck." The modern form (influenced by English verbs in -ish, e.g. distinguish, diminish) is attested from c.1530.
No wonder is thogh that she were astoned [Chaucer, "Clerk's Tale"]
Related: Astonished; astonishing; astonishingly.
astonishment (n.): 1590s; see astonish + -ment. Earlier it meant "paralysis" (1570s).
astound (v.): 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. Related: Astounded; astounding.
astral (adj.): "pertaining to the stars," c.1600, from Late Latin astralis, from Latin astrum "star," from Greek astron (see astro-). Meaning "pertaining to supersensible substances" is from 1690s, popularized late 19c. in Theosophy.
astray (adv.): c.1300, astraied "away from home; lost," 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.): 1560s, from Latin astrictionem (nominative astrictio), noun of action from past participle stem of astringere (see astringent).
Astrid: fem. proper name, from Norse, related to Old High German Ansitruda, from ansi "god" (see Asgard) + trut "beloved, dear."
astride (adv.): 1660s, from a- (1) "on" + stride (n.).
astringent (adj.): 1540s, from Latin astringentum (nominative astringens), present participle of astringere "to bind fast, tighten, contract," from ad- "to" (see ad-) + stringere "draw tight" (see strain (v.)). As a noun from 1620s.
astro-: 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," related to aster "star" (see star (n.)). 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.): 1903, from French astrobiologie; see astro- + biology. Related: Astrobiological; astrobiologist.
astrobleme (n.): 1961, from astro- + Greek bleme "throw of a missile; wound caused by a missile," from ballein "to throw" (see ballistics).
astroid (adj.): "star-shaped," 1897, from Greek astroeides, from astron "star" (see astro-) + -oeides (see -oid).
astrolabe (n.): mid-14c., from Old French astrelabe, from Medieval Latin astrolabium, from Greek astrolabos (organon) "star taking (instrument)," from astron "star" (see astro-) + lambanien "to take" (see analemma).
astrologer (n.): late 14c., from astrology + -er (1). Drove out French import astrologein, which, had it survived, probably would have yielded *astrologian; cf. Chaucer's "The wise Astrologen." Earliest recorded reference is to roosters as announcers of sunrise.
astrological (adj.): 1590s; see astrology + -ical. Related: Astrologically.
astrology (n.): late 14c., from Latin astrologia "astronomy, the science of the heavenly bodies," from Greek astrologia "telling of the stars," from astron "star" (see astro-) + -logia "treating of" (see -logy).

Originally identical with astronomy, it had also a special sense of "practical astronomy, astronomy applied to prediction of events." This was divided into natural astrology "the calculation and foretelling of natural phenomenon" (tides, eclipses, etc.), and judicial astrology "the art of judging occult influences of stars on human affairs" (also known as astromancy, 1650s). Differentiation between astrology and astronomy began late 1400s and by 17c. this word was limited to "reading influences of the stars and their effects on human destiny."
astronaut (n.): coined 1929 in science fiction, popularized from 1961 by U.S. space program, from astro- + nautes "sailor" (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.): 1929, see astronaut + -ics.
astronomer (n.): late 14c., from astronomy (q.v.), replacing French import astronomyen (c.1300), which, had it survived, probably would have yielded *astronomian. Still in Shakespeare used in places where we would write astrologer.
astronomical (adj.): 1550s, 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 Earth to Sun," used as a unit of measure of distance in space, is from 1909. Related: Astronomically.
astronomy (n.): c.1200, from Old French astrenomie, from Latin astronomia, from Greek astronomia, literally "star arrangement," from astron "star" (see astro-) + nomos "arranging, regulating," related to nemein "to deal out" (see numismatics). Used earlier than astrology and originally including it.
astrophotography (n.): 1858, from astro- + photography.
astrophysicist (n.): 1869, usually hyphenated at first, from astro- + physicist. Astrophysics is recorded from 1877.
Astroturf (n.): 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 a center of the U.S. space program.
astute (adj.): 1610s, from Latin astutus "crafty, wary, shrewd; sagacious, expert," from astus "cunning, cleverness, adroitness," of uncertain origin, perhaps from Greek asty "town," a word borrowed into Latin and with an overtone of "city sophistication" (cf. asteism). Related: Astutely; astuteness.
Astyanax: 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.): mid-12c., contraction of Old English on sundran (see sunder). Middle English used to know asunder for "distinguish, tell apart."
asylum (n.): early 15c., earlier asile (late 14c.), from Latin asylum "sanctuary," from Greek asylon "refuge," noun use of neuter of asylos "inviolable, safe from violence," especially of persons seeking protection, from a- "without" + syle "right of seizure." So literally "an inviolable place." General sense of "safe or secure place" is from 1640s; meaning "benevolent institution to shelter some class of persons" is from 1776.
asymmetrical (adj.): 1680s; see asymmetry + -ical. Other forms that have served as an adjective based on asymmetry are asymmetral (1620s), asymmetrous (1660s), and asymmetric (1875); only the last seems to have any currency. Related: Asymmetrically.
asymmetry (n.): 1650s, "want of symmetry or proportion," from Greek asymmetria, noun of quality from asymmetros "having no common measure; disproportionate, unsymmetrical," from a- "not" + symmetros "commensurable" (see symmetry).
asymptomatic (adj.): "without symptoms," 1856, from a-, privative prefix, + symptomatic.
asymptote (n.): "straight line continually approaching but never meeting a curve," 1650s, from Greek asymptotos "not falling together," from a- "not" + syn "with" + ptotos "fallen," verbal adjective from piptein "to fall" (see symptom). Related: Asymptotic.
asymptotic (adj.): 1670s, see asymptote + -ic. Related: Asymptotical; asymptotically.
asynchronous (adj.): 1748, from a-, privative prefix, + synchronous.
asyndetic (adj.): 1823; see asyndeton + -ic.
asyndeton (n.): "omission of conjunctions," 1580s, from Latin, from Greek asyndeton, neuter of asyndetos "unconnected," from a-, privative prefix (see a- (3)), + syndetos, from syndein "to bind together," from syn- "together" + dein "to bind."
asystole (n.): 1860, from Modern Latin, from Greek a-, privative prefix (see a- (3)), + systole "contraction" (see systole).
at (prep.): Old English æt, from Proto-Germanic *at (cf. Old Norse, Gothic at, Old Frisian et, Old High German az), from PIE *ad- "to, near, at" (cf. Latin ad "to, toward" Sanskrit adhi "near;" see ad-).

Lost in German and Dutch, which use their equivalent of to; in Scandinavian, however, to has been lost and at fills its place. In choosing between at church, in church, etc. at is properly distinguished from in or on by involving some practical connection; a worshipper is at church; a tourist is in the church.

The colloquial use of at after where ("where it's at") is attested from 1859. At last is recorded from late 13c.; adverbial phrase at least was in use by 1775. At in Middle English was used freely with prepositions (e.g. at after, which is in Shakespeare), but this has faded with the exception of at about, which was used in modern times by Trollope, Virginia Woolfe, D.H. Lawrence, and Evelyn Waugh, but nonetheless is regarded as a sign of incompetent writing by my copy editor bosses.
at all: "in any way," mid-14c., originally used only affirmatively (cf. I Sam. XX:6 in KJV: "If thy father at all misse me"); now it is overwhelmingly used only in the negative or in interrogatory expressions, or in literary attempts at Irish dialect.
at bay: late 14c., originally often at the bay; see bay (n.3). Figurative use, of human beings in difficulties, is from c.1400. The expression reflects the former more widespread use of at. Earlier the expression be at abai was used of the hunted animal, "be unable to escape," c.1300, from French.
at-: assimilated form of ad- "to, toward, before" before stems beginning in -t-; see ad-.