Online Etymology Dictionary

ale (n.): Old English ealu "ale, beer," from Proto-Germanic *aluth- (source also of Old Saxon alo, Old Norse öl), perhaps from PIE root meaning "bitter" (source also of Latin alumen "alum"), or from PIE *alu-t "ale," from root *alu-, which has connotations of "sorcery, magic, possession, intoxication." The word was borrowed from Germanic into Lithuanian (alus) and Old Church Slavonic (olu).
In the fifteenth century, and until the seventeenth, ale stood for the unhopped fermented malt liquor which had long been the native drink of these islands. Beer was the hopped malt liquor introduced from the Low Countires in the fifteenth century and popular first of all in the towns. By the eighteenth century, however, all malt liquor was hopped and there had been a silent mutation in the meaning of the two terms. For a time the terms became synonymous, in fact, but local habits of nomenclature still continued to perpetuate what had been a real difference: 'beer' was the malt liquor which tended to be found in towns, 'ale' was the term in general use in the country districts. [Peter Mathias, "The Brewing Industry in England," Cambridge University Press, 1959]
Meaning "festival or merry-meeting at which much ale was drunk" was in Old English (see bridal).
aleatory (adj.): "of uncertain outcome," literally "depending on the throw of a die," 1690s, from Latin aleatorius "pertaining to a gamester," from aleator "a dice player," from alea "a game with dice; chance, hazard, risk; a die, the dice;" perhaps literally "a joint-bone, a pivot-bone," and related to axis.
alectryomachy (n.): "cock-fighting," 1650s, from Greek alektryon "cock" (see alectryomancy) + -machy.
alectryomancy (n.): "divination by means of a cock and grains of corn," 1680s, from Latinized form of Greek alektryon "cock" + manteia "oracle" (see -mancy). The first element is literally "warder-off, fighter," related to alexein "to ward off, drive or keep off" (see Alexander, and compare Alekto, name of one of the three Furies). Perhaps originally a personal name, applied at first to the fighting cock, then to cocks generally.
alehouse (n.): also ale-house, Old English eala-huse; see ale + house (n.). An alehouse "is distinguished from a tavern, where they sell wine" [Johnson].
Alemanni: name of a Germanic tribe or confederation from the Elbe River region that in late Roman times settled along the upper Rhine in Alsace and part of Switzerland, from Proto-Germanic *Alamanniz, probably meaning "all-man" and likely denoting a coalition or alliance of tribes rather than a single group. But on another theory perhaps meaning rather "foreign men" (compare Allobroges, name of a Celtic tribe in what is now Savoy, in Latin literally "the aliens," in reference to their having driven out the original inhabitants), in which case the al- is cognate with the first element in Latin alius "the other" and English else.

The defeat of the Alemanni by a Frank-led army at Strasburg in 496 C.E. marks the conversion of Clovis and the rise of Frankish political power. The Alemanni were absorbed into the Frankish Kingdom in 796. Not historically important, but through proximity and frequent conflict with the Franks their name became the source of French Allemand, the usual word for "German, a German," Allemagne "Germany." In modern use, Alemannic refers to the dialects of modern southwestern Germany; Alamannic refers to the ancient tribes and their language.
alembic (n.): late 14c., earlier limbeck (mid-14c.), from Middle French alambic (13c.), via Old Spanish, from Arabic al-anbiq "distilling flask," from Greek ambix "cup," of unknown, possibly Semitic, origin. Often spelled limbeck 15c.-17c.
aleph (n.): Hebrew and Phoenician letter, c. 1300, from Semitic languages, pausal form of eleph "ox" (the character might have developed from a hieroglyph of an ox's head); also see alphabet.
alert (adv.): "on the watch," 1590s, from French alerte "vigilant" (17c.), from phrase à l'erte "on the watch," from Italian all'erta "to the height," from erta "lookout, high tower," noun use of fem. of erto, past participle of ergere "raise up," from Latin erigere "raise" (see erect). The adjective is attested from 1610s, the noun from 1803, and the verb from 1868. Related: Alerted; alerting.
alertly (adv.): 1787, from alert + -ly (2).
alertness (n.): 1714, from alert + -ness.
Alethea: fem. proper name, from Greek aletheia "truth, truthfulness," from alethes "true," literally "not concealing," from privative prefix a- "not" (see a- (3)) + lethe "forgetfulness, oblivion" (see latent).
Aleut: native of the Aleutian Islands, 1780, of unknown origin, probably from a native word. First applied by Russian explorers c. 1750, perhaps from Alut, name of a coastal village in Kamchatka [Bright]. Their name for themselves is unangax.
alewife (n.): herring-like fish of North America, 1630s, named from the word for female tavern keepers (late 14c.), from ale + wife; the fish so called in reference to its large abdomen.
Alexander: masc. proper name, from Latin, from Greek Alexandros "defender of men," from alexein "to ward off, keep off, turn (something) away, defend, protect" + aner (genitive andros) "man" (see anthropo-). The first element is related to Greek alke "protection, help, strength, power, courage," alkimos "strong;" cognate with Sanskrit raksati "protects," Old English ealgian "to defend." As a kind of cocktail, it is attested from 1930.
Alexandrine: in reference to a type of verse line, 1580s (adj.); 1660s (n.), said to be from Old French Roman d'Alexandre, name of a poem about Alexander the Great that was popular in the Middle Ages, which used a 12-syllable line of 6 feet (the French heroic verse); it was used in English to vary the heroic verse of 5 feet. The name also sometimes is said to be from Alexandre de Paris, 13c. French poet, who used such a line (and who also wrote one of the popular Alexander the Great poems).
Alexis: masc. proper name, from Greek alexis, from alexein "to ward off, keep, protect" (see Alexander). The Latin form was Alexius.
alfalfa (n.): 1845, from Spanish alfalfa, earlier alfalfez, from Arabic al-fisfisa "fresh fodder."
Alfred: masc. proper name, Old English Ælfræd, literally "elf-counsel," from ælf (see elf) + ræd "counsel," which is related to read (v.).
alga (n.): see algae.
algae (n.): (plural), 1794, from alga (singular), 1550s, from Latin alga "seaweed," which is of uncertain origin, perhaps from a PIE root meaning "to putrefy, rot."
algal (adj.): 1846, see alga + -al (1).
algebra (n.): 1550s, from Medieval Latin algebra, from Arabic al jabr ("in vulgar pronunciation, al-jebr" [Klein]) "reunion of broken parts," as in computation, used 9c. by Baghdad mathematician Abu Ja'far Muhammad ibn Musa al-Khwarizmi as the title of his famous treatise on equations ("Kitab al-Jabr w'al-Muqabala" "Rules of Reintegration and Reduction"), which also introduced Arabic numerals to the West. The accent shifted 17c. from second syllable to first. The word was used in English 15c.-16c. to mean "bone-setting," probably from Arab medical men in Spain.
algebraic (adj.): 1660s, from algebra + -ic. Earlier was algebraical (1570s).
Algeria: North African country, named for Algiers, city chosen by the French as its capital when they colonized it in 1830 + Latinate "country" suffix -ia. The city name is Arabic al-Jazair, literally "the islands," in reference to four islands formerly off the coast but joined to the mainland since 1525. A resident of the place formerly was an Algerine (1650s), and the word was practically synonymous with "pirate" in English and U.S. usage early 19c.
Algernon: masc. proper name, literally "with mustaches," from Old French als gernons, from a les "to the, with the" + gernon, variant of grenon "mustache," from Vulgar Latin *granonem, from a Germanic source (compare Old English granu "mustache").
Algol: Beta Persei, variable star in the constellation Perseus, late 14c., literally "the Demon," from Arabic al-ghul "the demon" (see ghoul). It corresponds, in modern representations of the constellation, to the gorgon's head Perseus is holding, but it probably was so called because it visibly varies in brightness every three days, which sets it apart from other bright stars. The computer language (1959) is a contraction of algo(rithmic) l(anguage); see algorithm.
Algonquian: also Algonkian, 1885, an ethnologist's word, modified from Algonquin + -ian. Both forms of the name have been used as adjectives and nouns. An American-Indian language family spread over a wide area of northeast and north-central North America, from Nova Scotia (Micmac) to Montana (Cheyenne).
Algonquin: one of an Indian people living near the Ottawa River in Canada, 1620s, from French Algonquin, perhaps a contraction of Algoumequin, from Micmac algoomeaking "at the place of spearing fish and eels." But Bright suggests Maliseet (Algonquian) elægomogwik "they are our relatives or allies."

Algonquian (1885) was the name taken by ethnologists to describe a large group of North American Indian peoples, including this tribe. Algonquin Hotel (59 W. 44th St., Manhattan) opened 1902 and named by manager Frank Case for the tribe that had lived in that area. A circle of journalists, authors, critics, and wits began meeting there daily in 1919 and continued through the twenties; they called themselves "The Vicious Circle," but to others they became "The Round Table."
algorithm (n.): 1690s, from French algorithme, refashioned (under mistaken connection with Greek arithmos "number") from Old French algorisme "the Arabic numeral system" (13c.), from Medieval Latin algorismus, a mangled transliteration of Arabic al-Khwarizmi "native of Khwarazm," surname of the mathematician whose works introduced sophisticated mathematics to the West (see algebra). The earlier form in Middle English was algorism (early 13c.), from Old French.
algorithmic (adj.): by 1799, from algorithm + -ic. In reference to symbolic rules or language, by 1881.
Alhambra: palace of the Moorish kings in Granada, Spanish, from Arabic (al kal'at) al hamra "the red (castle)," from fem. of ahmuru "red." So called for the sun-dried bricks of which its outer walls were built.
alias (adv.): mid-15c., "otherwise called," from Latin alias "at another time, in another way," from alius "(an)other," from PIE *al- (1) "beyond" (source also of Sanskrit anya "other, different," Avestan anya-, Armenian ail, Greek allos "another," Gothic aljis "other," Old English elles "otherwise, else," Modern English else).
alias (n.): "assumed name," c. 1600, from alias (adv.).
alibi (n.): 1743, "the plea of having been elsewhere when an action took place," from Latin alibi "elsewhere, somewhere else," locative of alius "(an)other" (see alias (adv.)). The weakened sense of "excuse" is attested since 1912, but technically any proof of innocence that doesn't involve being "elsewhere" is an excuse, not an alibi.
Alice: fem. proper name, from Old French Aliz, from Old High German Adalhaid, literally "nobility, of noble kind" (see Adelaide). Among the top 20 most popular names for girls born in the U.S. from c. 1880-1920. "Alice's Adventures in Wonderland" published 1865.
alien (adj.): mid-14c., "strange, foreign," from Old French alien "alien, strange, foreign; an alien, stranger, foreigner," from Latin alienus "of or belonging to another, foreign, alien, strange," also, as a noun, "a stranger, foreigner," adjectival form of alius "(an)other" (see alias (adv.)). Meaning "not of the Earth" first recorded 1920. An alien priory (c. 1500) is one owing obedience to a mother abbey in a foreign country.
alien (n.): "foreigner, citizen of a foreign land," from alien (adj.). In the science fiction sense, from 1953.
alienable (adj.): "that can be surrendered or given up," 1610s; see alien (adj.) + -able. Related: Alienability.
alienate (v.): 1540s, "make estranged" (in feelings or affections), from Latin alienatus, past participle of alienare "to make another's, estrange," from alienus "of or belonging to another person or place," from alius "(an)other" (see alias (adv.)). Related: Alienated; alienating.
alienation (n.): "transfer of ownership," late 14c., from Old French alienacion and directly from Latin alienationem (nominative alienatio) "a transfer, surrender," noun of action from past participle stem of alienare (see alienate). It also meant "loss or derangement of mental faculties, insanity" (late 15c.), hence alienist. Phrase alienation of affection as a U.S. legal term in divorce cases for "falling in love with someone else" dates to 1861.
alienist (n.): "one who treats mental illness, 'mad doctor,' " 1864, from French aliéniste, from alienation in the sense of "insanity, loss of mental faculty," a sense attested in English from late 15c. (see alienate).
alight (v.): "to descend, dismount," Old English alihtan, originally "to lighten, take off, take away," from a- "down, aside" (see a- (1)) + lihtan "get off, make light" (see light (v.)). The notion is of getting down off a horse or vehicle, thus lightening it. Of aircraft (originally balloons) from 1786. Related: Alighted; alighting.
alight (adj.): "on fire," early 15c., apparently from Middle English aliht, past participle of alihton (Old English on-lihtan) "to light up," also "to shine upon" (see light (n.)).
align (v.): early 15c., "to copulate" (of wolves, dogs), literally "to range (things) in a line," from Middle French aligner, from Old French alignier "set, lay in line," from à "to" (see ad-) + lignier "to line," from Latin lineare, from linea (see line (n.)). Transitive or reflexive sense of "to fall into line" is from 1853. International political sense is attested from 1934. No justification for the French spelling, and aline was an early native form. Related: Aligned; aligning.
alignment (n.): 1790, "arrangement in a line," from French alignement, from aligner (see align). Political sense is from 1933.
alike (adj.): c. 1300, aliche, from Old English gelic and/or onlice "similar," from Proto-Germanic *galikam "associated form" (source also of Old Frisian gelik, German gleich, Gothic galeiks, Old Norse glikr; see like (adj.)).
aliment (n.): "food," late 15c., from Latin alimentum "nourishment," in plural, "food, provisions," from alere "to nourish" (see alimentary).
alimentary (adj.): 1610s, from Medieval Latin alimentarius "pertaining to food," from Latin alimentum "nourishment," from alere "to nourish, rear, support, maintain," from PIE root *al- "to grow, nourish" (see old).
alimony (n.): 1650s, "nourishment," also "allowance to a wife from a husband's estate, or in certain cases of separation," from Latin alimonia "food, support, nourishment, sustenance," from alere "to nourish" (see old) + -monia suffix signifying action, state, condition (cognate with Greek -men). Derived form palimony coined 1979.