Online Etymology Dictionary

air conditioner (n.): from air (n.1) + agent noun from condition; along with air-conditioning, first attested 1909, originally an industrial process; main modern use in residences and office buildings is from 1930s.
air force (n.): 1917, from air (n.1) + force (n.); first attested with creation of the Royal Air Force. There was no United States Air Force until after World War II. The Air Corps was an arm of the U.S. Army. In 1942, the War Department reorganized it and renamed it Army Air Forces. The National Security Act of 1947 created the Department of the Air Force, headed by a Secretary of the Air Force, and the U.S.A.F.
air freshener (n.): 1949, from air (n.1) + agent noun from freshen.
air mail (n.): also air-mail, 1913, from air (n.1) + mail (n.1).
air raid (n.): 1914, from air (n.1) + raid (n.); originally in reference to British attacks Sept. 22, 1914, on Zeppelin bases at Cologne and Düsseldorf in World War I. The German word is Fliegerangriff "aviator-attack," and if Old English had survived into the 20th century our word instead might be fleogendeongrype.
One didn't dare to inhale for fear of breathing it in. It was the sound of eighteen hundred airplanes approaching Hamburg from the south at an unimaginable height. We had already experienced two hundred or even more air raids, among them some very heavy ones, but this was something completely new. And yet there was an immediate recognition: this was what everyone had been waiting for, what had hung for months like a shadow over everything we did, making us weary. It was the end. [Hans Erich Nossack, "Der Untergang," 1942]
airborne (adj.): 1640s, "carried through the air," from air (n.1) + borne. Of military units, from 1937.
aircraft (n.): 1851, originally in reference to airships and balloons, from air (n.1) + craft (n.); a term from boating, as were many early aviation words. Of airplanes from 1907 and since 1930s exclusively of them. Aircraft carrier is attested from 1919 (H.M.S. Hermes, launched September 1919, was the first ship to be built from the hull up as an aircraft carrier).
Airedale: type of terrier, 1880, named for Airedale, a district in West Riding, Yorkshire.
Name registered by Kennel Club (1886), for earlier Bingley (where first bred), or broken-haired terrier. [Weekley]
airfoil (n.): 1922, U.S. form of aerofoil.
airhead (n.): "empty-headed person," 1972, from air (n.1) + head (n.). Earlier as a term in mining (mid-19c.) and as a military term based on beachhead (1950).
airily (adv.): 1766, from airy "with ostentatious air" (see air (n.2)) + -ly (2).
airing (n.): "action of exposing to air," c.1600, from present participle of air (v.). Meaning "display, public exposure is from 1870.
airlift (n.): also air-lift, 1893 as a type of pumping device; 1945 in the sense "transportation of supplies by air," from air (n.1) + lift (n.). As a verb by 1949; popularized in reference to the response to the West Berlin blockade. Related: Air-lifted; air-lifting.
airline (n.): also air-line, 1813, "beeline, straight line from place to place" (as through the air, rather than over terrain; in later 19c. especially in reference to railways that ran directly between big cities in the U.S. instead of meandering from town to town in search of stock subscriptions as early railways typically did), from air (n.1) + line (n.). Meaning "public aircraft transportation company" is from 1914.
airplane (n.): 1907, from air (n.1) + plane (n.1); though the original references are British, the word caught on in American English, where it largely superseded earlier aeroplane (1873 in this sense and still common in British English). Aircraft "airplane" also is from 1907. Lord Byron, speculatively, used air-vessel (1822).
airplay (n.): 1950 in radio sense, from air (n.1) + play.
airport (n.): 1919, from air (n.1) + port (n.1). First reference is to Bader Field, outside Atlantic City, New Jersey, U.S., which opened in 1910.
airship (n.): also air-ship, 1888, translating German Luftschiff "motor-driver dirigible;" see air (n.1) + ship (n.).
airtight (adj.): also air-tight, "impervious to air," 1760, from air (n.1) + tight. Figurative sense of "incontrovertible" (of arguments, alabis, etc.) is from 1929.
airy (adj.): late 14c., "of the air, made of air," from air (n.1) + -y (2). Meaning "breezy" is attested from 1590s; that of "lively" is from 1640s. Sense of "vain, unsubstantial" is from 1580s. Disparaging airy-fairy is attested from 1920 (earlier in a sense of "delicate or light as a fairy," which is how Tennyson used it in 1830).
aisle (n.): late 14c., ele, "lateral division of a church (usually separated by a row of pillars), from Old French ele "wing (of a bird or an army), side of a ship" (12c., Modern French aile), from Latin ala, related to axilla "wing, upper arm, armpit; wing of an army," from PIE *aks- "axis" (see axis), via a suffixed form *aks-la-. The root meaning in "turning" connects it with axle and axis.

Confused 15c. with unrelated ile "island" (perhaps from notion of a "detached" part of a church), and so it took an -s- when isle did, c.1700; by 1750 it had acquired an a-, on the model of French cognate aile. The word also was confused with alley, which gave it the sense of "passage between rows of pews or seats" (1731), which was thence extended to railway cars, theaters, etc.
ajar: 1718, perhaps from Scottish dialectal a char "slightly open," earlier on char (early 16c.), from Middle English char, from Old English cier "a turn."
Ajax: name of two Greek heroes in the Trojan War (Great Ajax, son of Telamon, and Little Ajax, son of Oileus), Latin, from Greek Aias, perhaps originally the name of an earth-god, from aia "earth." The Elizabethans punned on the name as a jakes "a privy."
akimbo: c.1400, in kenebowe, of unknown origin, perhaps from Middle English phrase in keen bow "at a sharp angle," or from a Scandinavian word akin to Icelandic kengboginn "bow-bent," but this seems not to have been used in this exact sense. Many languages use a teapot metaphor for this, such as French faire le pot a deux anses "to play the pot with two handles."
akin (adj.): 1550s, from phrase of kin; see kin.
Akkadian: 1855, from Akkad (Sumerian Agde, Biblical Acca), name of city founded by Sargon I in northern Babylonia, of unknown origin; applied by modern scholars to the east Semitic language spoken there (c.2300-2100 B.C.E.) and preserved in cuneiform inscriptions.
al dente: 1935, Italian, literally "to the tooth," from Latin dent (see tooth).
al fresco: 1753, Italian, literally "in the fresh (air)." Italian al represents a contraction of words from Latin ad "to" (see ad-) + ille "that." Alfresco also meant "painted on plaster that was still fresh or moist" (1764; see fresco).
al Qaeda: alternative Latin alphabet transliteration of Arabic al Qaida (q.v.).
al Qaida: also Al-Qaeda; name of a loosely structured jihadist movement founded c.1989 by Osama bin Laden; from Arabic, literally "the base." A common Arabic term among Muslim radicals from the wider Islamic world who came to Afghanistan in 1980s and fought alongside local rebels against the Soviets, and who regarded themselves and their struggle not merely in Afghan terms but as the "base" or foundation of a wider jihad and revival in Islam. Used by Bin Laden's mentor, Abdallah Azzam (1941-1989), who referred to the "vanguard" which "constitutes the strong foundation [al-qaida al-sulbah] for the expected society." In U.S., the term first turns up in a CIA report in 1996.
Every Muslim, from the moment they realise the distinction in their hearts, hates Americans, hates Jews, and hates Christians. This is a part of our belief and our religion. For as long as I can remember, I have felt tormented and at war, and have felt hatred and animosity for Americans. [Osama bin Laden, interview aired on Al-Jazeera, December 1998]
Alabama: created and named as a U.S. territory 1817 by a division of Mississippi Territory; ultimately named for one of the native peoples who lived there, who speak Muskogean. Their name probably is from a Choctaw term meaning "plant-cutters."
alabaster (n.): translucent whitish kind of gypsum used for vases, ornaments, and busts, late 14c., from Old French alabastre (12c., Modern French albâtre), from Latin alabaster "colored rock used to make boxes and vessels for unguents," from Greek alabastros (earlier albatos) "vase for perfumes," perhaps from Egyptian 'a-labaste "vessel of the goddess Bast." Used figuratively for whiteness and smoothness from 1570s. "The spelling in 16-17th c. is almost always alablaster ..." [OED].
alabastrine (adj.): 1590s, from Medieval Latin alabastrinus, from alabaster (see alabaster).
alack: late 15c., from ah, lack, from lack in Middle English sense of "loss, failure, reproach, shame." Originally an expression of dissatisfaction, later of regret or unpleasant surprise.
alacrity (n.): mid-15c., from Latin alacritatem (nominative alacritas) "liveliness, ardor, eagerness," from alacer (genitive alacris) "cheerful, brisk, lively;" of uncertain origin, perhaps cognate with Gothic aljan "zeal," Old English ellen "courage, zeal, strength," Old High German ellian.
Aladdin: name of a hero in stories from the Arabian Nights, from Arabic Ala' al Din, literally "nobility of faith."
Alamo: nickname of Franciscan Mission San Antonio de Valeroin (begun 1718, dissolved 1793) in San Antonio, Texas; American Spanish, literally "poplar" (in New Spain, also "cottonwood"), from alno "the black poplar," from Latin alnus "alder" (cf. alder).

Perhaps so called in reference to trees growing nearby (cf. Alamogordo, New Mexico, literally "big poplar," and Spanish alameda "a public walk with a row of trees on each side"); but the popular name seems to date from the period 1803-13, when the old mission was the base for a Spanish cavalry company from the Mexican town of Alamo de Parras in Nueva Vizcaya.
Alan: masc. proper name, 1066, from Old Breton Alan, name of a popular Welsh and Breton saint; brought to England by the large contingent of Bretons who fought alongside William the Conqueror.
alar (adj.): "wing-like," c.1840; "of or pertaining to wings," 1847, from Latin alaris, from ala "wing, armpit, wing of an army" (source of Spanish ala, French aile), from *axla, originally "joint of the wing or arm;" from PIE *aks- (see axis).
Alaric: Visigothic masc. proper name, literally "all-ruler," from Proto-Germanic *ala- "all" (see all) + *rikja "rule" (see rich).
alarm (n.): early 14c., from Old French alarme (14c.), from Italian all'arme "to arms!" (literally "to the arms"). An interjection that came to be used as the word for the call or warning (cf. alert). Extended 16c. to "any sound to warn of danger or to arouse." Weakened sense of "apprehension, unease" is from 1833. Variant alarum is due to the rolling -r- in the vocalized form. Sometimes in early years anglicized as all-arm. Alarm clock is attested from 1690s (as A Larum clock).
alarm (v.): 1580s, from alarm (n.). Related: Alarmed; alarming.
alarmed (adj.): "disturbed by prospects of peril," 1640s, past participle adjective from alarm (v.).
alarmingly (adv.): 1787, from alarming, present participle adjective from alarm (v.), + -ly (2).
alarmist (n.): "one addicted to sounding alarms," 1793, from alarm (n.) + -ist.
alarum (n.): obsolete and poetic spelling of alarm (n.).
alas: mid-13c., from Old French ha, las (later French hélas), from ha "ah" + las "unfortunate," originally "tired, weary," from Latin lassus "weary" (see late). At first an expression of weariness rather than woe.
Alaska: name first applied 18c. by Russian explorers, from Aleut alaxsxaq, literally "the object toward which the action of the sea is directed" [Bright]. Baked Alaska attested by 1896, so called either for its whiteness or from being cold inside.
Alastor: in Greek tradition, son of Neleus, brother of Nestor, slain by Herakles. The name is perhaps literally "not to forget," from privative prefix a- "not" + root of lathein "to forget" (see Lethe), hence its use figuratively in sense of "an avenging spirit." Or else it might be connected with alaomai "to wander, roam," figuratively "to be distraught."
alb (n.): late Old English albe, from Late Latin alba (in tunica alba or vestis alba "white vestment"), fem. of albus "white," from PIE root *albho- "white" (cf. Greek alphos "white leprosy," alphiton "barley meal;" Old High German albiz, Old English elfet "swan," literally "the white bird;" Old Church Slavonic and Russian lebedi, Polish łabędź "swan;" Hittite alpash "cloud").