alkahest (n.)
"universal solvent sought by alchemists," 1640s, from French alcahest, from Medieval Latin alcahest, a pseudo-Arabic word coined by Paracelsus (compare alchemy).
alkalescent (adj.)
1732, from alkali + -escent. Related: Alkalescence.
alkali (n.)
late 14c., "soda ash," from Medieval Latin alkali, from Arabic al-qaliy "the ashes, burnt ashes" (of saltwort, which abounds in soda due to growing in alkaline soils), from qala "to roast in a pan." Later extended to similar substances, natural or manufactured. The modern chemistry sense is from 1813.
alkaline (adj.)
1670s, "pertaining to alkalis," from alkali + -ine (1). Of soils, from 1850. Related: Alkalinity.
alkalize (v.)
"render alkaline," 1725 (implied in alkalized), from French alcaliser; see alkali.
alkaloid (n.)
1831, from alkali (q.v.) + -oid. "A general term applied to basic compounds of vegetable origin, bitter in taste, and having powerful effects on the animal system" [Flood], including morphine and nicotine. As an adjective by 1859.
alkanet (n.)
mid-14c., "the plant alkanet or its root" (used as a dye material and a styptic), via Medieval Latin, from Spanish alcaneta, diminutive of alcana, from Arabic al-hinna (see henna). As the name of the plant itself, from 1560s.
all (adj./adv.)
Old English eall "every, entire, the whole quantity of" (adj.), "fully, wholly, entirely" (adv.), from Proto-Germanic *alnaz (source also of Old Frisian, Old High German al; German all, alle; Old Norse allr; Gothic alls), with no certain connection outside Germanic. As a noun, in Old English, "all that is, everything."

Combinations with all meaning "wholly, without limit" were common in Old English (such as eall-halig "all-holy," eall-mihtig "all-mighty") and the method continued to form new compound words throughout the history of English. Middle English had al-wher "wherever; whenever" (early 14c.); al-soon "as soon as possible," al-what (c. 1300) "all sorts of things, whatever." Of the common modern phrases with it, at all "in any way" is from mid-14c., and all "and everything (else)" is from 1530s, all but "everything short of" is from 1590s. First record of all out "to one's full powers" is 1880. All clear as a signal of "no danger" is recorded from 1902. All right, indicative of approval, is attested from 1953.

The use of a, a' as an abbreviation of all (as in Burns' "A Man's a Man for A' that") is a modern Scottishism but has history in English to 13c.
all-American (n.)
1888, plural, as the name of a barnstorming baseball team composed of players from various teams across the United States. From all + American.
all-fired (adj.)
1837, U.S. slang, said to be a euphemism for hell-fired, but perhaps it is what it says, with all as an intensive.
all-in (adj.)
"without restrictions," 1890, from the adverbial phrase; see all + in (adv.).
all-inclusive (adj.)
1813, from all + inclusive. Related: All-inclusively; all-inclusiveness.
all-nighter (n.)
1930, "person who stays up all night," later "incident of staying up all night," from the adverbial phrase; see all + night.
all-over (adj.)
"covering every part," 1859, from the adverbial phrase; see all + over (adv.). As a noun, by 1838 as the trade name for a button, etc., gilded on both sides rather than only the top. All-overish "generally, indefinitely indisposed" is from 1820. Related: All-overishness.
all-purpose (adj.)
"suitable for every use or occasion," 1877, from all + purpose (n.).
all-round (adj.)
1728, "everywhere," from all + round (adj.). Meaning "able to do many things well, versatile" is from 1867. Also sometimes all-around. All-rounder is from 1855 as a type of men's collar; 1875 as "person who is good at everything."
all-sorts (n.)
name in old taverns and beer-shops for a beverage composed of remnants of other liquors mixed together, 1823, from the adjectival phrase; see all + plural of sort (n.).
all-star (adj.)
1893, originally of theatrical casts, from all + star (n.) in the "celebrated person" sense. From 1898 in reference to sports teams.
all-time (adj.)
"during recorded time," 1910, American English, from all + time (n.). Earlier it had been used in a sense "full-time," of employment, or in opposition to one-time (1883). Middle English had al-time (adv.) "at all times, always; all the time" (c. 1400).
Allah
Arabic name for the Supreme Being, 1702, Alha, from Arabic Allah, contraction of al-Ilah, literally "the God," from al "the" + Ilah "God," which is cognate with Aramaic elah, Hebrew eloah (see Elohim).
allative (adj.)
in reference to the grammatical case expressing "motion towards," 1854, with -ive + Latin allat-, past participle stem of the irregular verb adferre/affere "to bring to;" from assimilated form of ad "to" (see ad-) + latus "borne, carried" (see oblate (n.)).
allay (v.)
Middle English alegen, from Old English alecgan "to put, place, put down; remit, give up, suppress, abolish; diminish, lessen," from a- "down, aside" (see a- (1)) + lecgan "to lay" (see lay (v.)). A common Germanic compound (cognates: Gothic uslagjan "lay down," Old High German irleccan, German erlegen "to bring down").

Early Middle English pronunciations of -y- and -g- were not always distinct, and the word was confused in Middle English with various senses of Romanic-derived alloy (v.) and especially a now-obsolete verb allege "to alleviate, lighten" (from Latin alleviare, from ad "to" + levis "light" in weight; from PIE root *legwh- "not heavy, having little weight").
Amid the overlapping of meanings that thus arose, there was developed a perplexing network of uses of allay and allege, that belong entirely to no one of the original vbs., but combine the senses of two or more of them. [OED]
Hence senses "lighten, alleviate; mix, temper, weaken." The confusion with the Latin words probably also accounts for the unetymological double -l-, attested from 17c. Related: Allayed; allaying.
allegation (n.)
early 15c., "action of alleging, formal declaration in court," from Old French alegacion "allegation, affirmation" (Modern French allégation) and directly from Latin allegationem (nominative allegatio) "a sending, dispatching," noun of action from past participle stem of allegare (see allege). Specifically in law, "assertion of a party to a suit or action, which he intends to prove." In general (non-legal) use, since 17c., often suggesting an assertion without proof.
allege (v.)
c. 1300, "make a formal declaration in court;" mid-14c., "pronounce positively, claim as true," with or without proof; it has the form of one French verb and the meaning of another. The form is Anglo-French aleger, Old French eslegier "to clear at law" (from a compound of Latin ex "out of;" see ex- + litigare "bring suit" (see litigation).

However eslegier meant "acquit, clear of charges in a lawsuit," and the Middle English word somehow acquired the meaning of French alléguer, from Latin allegare/adlegare "send for, bring forth, name, produce in evidence, send on business," from ad "to" (see ad-) + legare "to depute, send" (see legate). Related: Alleged; alleging.
alleged (adj.)
mid-15c., "quoted," past participle adjective from allege. Attested from 1610s in sense of "brought forth in court;" 1670s as "asserted but not proved."
allegedly (adv.)
1828, from alleged + -ly (2).
alleger (n.)
"one who alleges or affirms," 1570s, agent noun from allege. The Latinate form, allegator (1680s) rarely is used, for some reason.
allegiance (n.)
"ties or obligations of a citizen or subject to a government or sovereign," late 14c., formed in English from Anglo-French legaunce "loyalty of a liege-man to his lord," from Old French legeance, from liege (see liege (adj.)). Corrupted in spelling by confusion with the now-obsolete legal term allegeance "alleviation, mitigation" (for which see allay (v.)). General figurative sense of "recognition of claims to respect or duty, observance of obligation" is attested from 1732. French allégeance in this sense is said to be from English.
allegorical (adj.)
1520s, earlier allegoric (late 14c.); from French allégorique, from Latin allegoricus, from Greek allegorikos, from allegoria "figurative language, description of one thing in terms of another" (see allegory). Related: Allegorically. Allegorical interpretation draws spiritual or figurative meaning from historical matter.
allegorize (n.)
1570s; see allegory + -ize. Related: Allegorized; allegorizing.
allegory (n.)
"figurative treatment of an unmentioned subject under the guise of another similar to it in some way," late 14c., from Old French allegorie (12c.), from Latin allegoria, from Greek allegoria "figurative language, description of one thing under the image of another," literally "a speaking about something else," from allos "another, different" (from PIE root *al- (1) "beyond") + agoreuein "speak openly, speak in the assembly," from agora "assembly" (see agora). Related: Allegorist.
allegretto
1740, from Italian allegretto, diminutive of allegro "brisk, sprightly" (q.v.), so, "not so quick as allegro."
allegro
1721 as a musical term, from Italian allegro "brisk, sprightly, cheerful," from Latin alacrem (nominative alacer) "lively, cheerful, brisk" (see alacrity). The same Latin word came into English 17c. as aleger "lively, brisk," from Old French alegre, from Latin Related: alacris; and Milton used "L'Allegro" in its literal sense as a poem title (1632).
allele (n.)
1931 in genetics, from German allel, abbreviation of allelomorph "alternative form of a gene" (1902), coined from Greek allel- "one another" (from allos "other;" from PIE root *al- (1) "beyond") + morphe "form" (see Morpheus).
alleluia (interj.)
late 14c., from Latin alleluja, from Greek allelouia, from Hebrew hallelu-yah "praise Jehovah" (see hallelujah). Related: Alleluiatic.
allemande (n.)
name for a German dance in 3/4 time, 1775, from French Allemande, fem. of allemand "German" (see Alemanni). As a piece of music in a suite, 1680s. As a figure in country or square dancing, from 1808.
Allen
masc. proper name and surname, variant of Alan (q.v.). In reference to a wrench, key, screw, etc. with a hexagonal socket or head, 1913, from the Allen Manufacturing Company of Hartford, Connecticut, U.S.
allergen (n.)
substance causing allergy, 1912, from allergy on model of antigen.
allergic (adj.)
1911, from allergy (q.v.) + -ic; perhaps modeled on French allergique (1906). Figurative use, "antipathetic, repulsed" is from 1936.
allergist (n.)
1937, from allergy + -ist.
allergy (n.)
1911, from German Allergie, coined 1906 by Austrian pediatrician Clemens E. von Pirquet (1874-1929) as an abstract noun from Greek allos "other, different, strange" (from PIE root *al- (1) "beyond") + ergon "activity," from PIE root *werg- "to do."
alleviate (v.)
early 15c., " to mitigate, relieve (sorrows, suffering, etc.)," from Late Latin alleviatus, past participle of alleviare "lift up, raise," figuratively "to lighten (a burden), comfort, console," from assimilated form of Latin ad "to" (see ad-) + levis "light" in weight (from PIE root *legwh- "not heavy, having little weight"). Related: Alleviated; alleviating.
alleviation (n.)
early 15c., "mitigation, relief," from Medieval Latin alleviationem (nominative alleviatio), noun of action from past participle stem of alleviare "lift up, raise," figuratively "to lighten (a burden), comfort, console," from assimilated form of Latin ad "to" (see ad-) + levis "light" in weight (from PIE root *legwh- "not heavy, having little weight").
alley (n.2)
also ally, type of large playing marble (generally one of stone as opposed to terra cotta), 1720, said to be a shortening of alabaster.
alley (n.1)
mid-14c., "passage in a house; open passage between buildings; walkway in a garden," from Old French alee (13c., Modern French allée) "a path, passage, way, corridor," also "a going," from fem. of ale, past participle of aler "to go," which is of uncertain origin. It might be a contraction of Latin ambulare "to walk" (Watkins, see amble (v.)), or it might be from Gallo-Roman allari, a back-formation from Latin allatus "having been brought to" [Barnhart]. Compare sense evolution of gate.

Applied by c. 1500 to "long narrow enclosure for playing at bowls, skittles, etc." Used in place names from c. 1500. "In U.S. applied to what in London is called a Mews" [OED], and in American English especially of a back-lane parallel to a main street (1729). To be up someone's alley "in someone's neighborhood" (literally or figuratively) is from 1931; alley-cat (n.) is attested by 1890.
alleyway (n.)
also alley-way, "small, short alley," as between two houses, 1788, from alley (n.1) + way (n.).
allgates (adv.)
c. 1200, allgate "all the time, on all occasions," mid-13c. "in every way," probably from the Old Norse phrase alla gotu (see all + gate (n.) "a way"). With adverbial genitive -s from late 14c. Compare always).
alliance (n.)
c. 1300, "bond of marriage" (between ruling houses or noble families), from Old French aliance (12c., Modern French alliance) "alliance, bond; marriage, union," from aliier (Modern French allier) "combine, unite" (see ally (v.)).

General sense of "combination for a common object" is from mid-14c., as are those of "bond or treaty between rulers or nations, contracted by treaty" and "aggregate of persons allied." Unlike its synonyms, "rarely used of a combination for evil" [Century Dictionary]. Meaning "state of being allied or connected" is from 1670s. The Latin word was alligantia.
allied (adj.)
c. 1300, past participle adjective from ally (v.). Originally of kindred (compare alliance); in reference to a league or formal treaty, it is first recorded late 14c.
alligator (n.)
1560s, "large carnivorous reptile of the Americas," lagarto, aligarto, a corruption of Spanish el lagarto (de Indias) "the lizard (of the Indies)," from Latin lacertus (see lizard), with Spanish definite article el, from Latin ille (see le).

The modern form of the English word is attested from 1620s, with unetymological -r as in tater, feller, etc. (Alligarter was an early variant) and an overall Latin appearance. The slang meaning "non-playing devotee of swing music" is attested from 1936; the phrase see you later, alligator is from a 1956 song title.