Online Etymology Dictionary

alongside (adv.): 1707, from along + side (n.). A word formed from a phrase. Originally mostly nautical.
aloof (adj.): 1530s, from a- (1) + Middle English loof "weather gage," also "windward direction," probably from Dutch loef (Middle Dutch lof) "the weather side of a ship." Originally a nautical order to keep the ship's head to the wind, thus to stay clear of a lee-shore or some other quarter; hence the figurative sense of "at a distance, apart" (1580s). Related: Aloofly; aloofness.
aloud (adv.): late 14c., from a- (1) + loud.
Aloysius: masc. proper name, from Medieval Latin Aloisius, from Old French Loois (see Louis).
alp (n.): 1590s, "any high, snow-capped mountain," from Alps, from French Alpes, from Latin Alpes "the Alps," perhaps from altus "high," or albus "white" or from a Celtic word (according to Servius), or a pre-Indo-European root. Alps, the European mountain range, attested by that name in English from 1550s.
alpaca (n.): 1792, from Spanish alpaca, probably from Aymara allpaca, related to Quechua p'ake "yellowish-red." The al- is perhaps from influence of Arabic definite article (see almond). Attested in English from 1753 in the form pacos.
Alpenstock (n.): "long iron-pointed staff used for hiking in mountains," 1829, German, literally "Alpine stick."
alpha (n.): c. 1300, from Latin alpha, from Greek alpha, from Hebrew or Phoenician aleph (see aleph). The Greeks added -a because Greek words cannot end in most consonants. Sense of "beginning of anything" is from late 14c., often paired with omega (last letter in the Greek alphabet) as "the end." Sense of "first in a sequence" is from 1620s. Alpha male was in use by c. 1960 among scientists studying animals; applied to humans in society from c. 1992.
alphabet (n.): 1570s, from Late Latin alphabetum (Tertullian), from Greek alphabetos, from alpha + beta. Alphabet soup first attested 1907. Words for it in Old English included stæfræw, literally "row of letters," stæfrof "array of letters."
It was a wise though a lazy cleric whom Luther mentions in his "Table Talk,"--the monk who, instead of reciting his breviary, used to run over the alphabet and then say, "O my God, take this alphabet, and put it together how you will." [William S. Walsh, "Handy-Book of Literary Curiosities," 1892]
alphabetical (adj.): 1560s, from alphabet + -ical. Related: Alphabetically.
alphabetize (v.): 1866, from alphabet + -ize. Related: Alphabetized; alphabetizing.
alphanumeric (adj.): 1912, contracted from alphabet + numeric (see numerical).
Alphonso: masc. proper name, from Spanish Alfonso, from a Germanic source (compare Old High German Adalfuns, from adal "noble;" see atheling + funs "ready"). The Alphonsine tables are named for Alphonso the Wise, 13c. king of Castile.
Alpine (adj.): "of the Alps," early 15c., from Latin Alpinus; see Alp. Earlier was Alpish (1590s).
Alps: see Alp.
already (adv.): c. 1300, compound of all + ready (adj.); literally "fully ready." Compare Norwegian, Danish allerede "already." Colloquial use in U.S. as a terminal emphatic (as in enough, already!) is attested from 1903, translating Yiddish shoyn, which is used in same sense. The pattern also is attested in Pennsylvania German and in South African.
alright: frequent spelling of all right, attested from 1893.
There are no such forms as all-right, or allright, or alright, though even the last, if seldom allowed by the compositors to appear in print, is often seen ... in MS. [Fowler]
Alsace: region between France and Germany (disputed by them 18c.-19c.), Medieval Latin Alsatia, from Old High German *Ali-sazzo "inhabitant of the other (bank of the Rhine)," from Proto-Germanic *alja "other" + Old High German -sazzo "inhabitant," literally "one who sits." Alsatian was adopted 1917 by the Kennel Club for "German Shepherd dog" to avoid the wartime associations of German; the breed has no connection with Alsace.
also (adv.): Old English eallswa "just as, even as, as if, so as, likewise," compound of all + so. The demonstrative sense of "similarly" weakened to "in addition to" in 12c., replacing eke. The compound has parallel forms in German also, Dutch alzoo.
also-ran (n.): 1896, originally in reference to horse-races, from also + past tense of run (v.). Probably from the way non-placing horses were listed in race results.
Altaic: 1832 as a linguistic family, from French Altaïque, from Altaïen, from Altai, name of a mountain range in Asia.
Altair: bright star in the constellation Aquila, 16c., from Arabic Al Nasr al Tair "the Flying Eagle," from tair, participle of tara "it flew."
altar (n.): Old English alter, altar, from Latin altare (plural altaria) "high altar, altar for sacrifice to the great gods," perhaps originally meaning "burnt offerings" (compare Latin adolere "to worship, to offer sacrifice, to honor by burning sacrifices to"), but influenced by Latin altus "high." In Middle English, often auter, from Old French auter. Reintroduced from Latin 1500s. As a symbol of marriage, by 1820.
alter (v.): late 14c., "to change (something)," from Old French alterer "change, alter," from Medieval Latin alterare "to change," from Latin alter "the other (of the two)," from PIE *al- "beyond" (see alias (adv.)) + comparative suffix -ter (as in other). Intransitive sense "to become otherwise" first recorded 1580s. Related: Altered; altering.
alter ego: 1530s, from Latin phrase (used by Cicero), "a second self, a trusted friend" (compare Greek allos ego); see alter and ego.
alterable (adj.): 1520s, from alter + -able. Related: Alterably; alterability.
alteration (n.): late 14c., "action of altering," from Old French alteracion (14c.) "change, alteration," and directly from Medieval Latin alterationem (nominative alteratio), noun of action from past participle stem of Late Latin alterare (see alter). Meaning "change in character or appearance" is from 1530s; that of "change in ready-made clothes to suit a customer's specifications" is from 1901. Related: Alterations.
altercate (v.): 1520s, "to contend with words," from Latin altercatus, past participle of altercari (see altercation).
altercation (n.): late 14c., from Old French altercacion (12c.) and directly from Latin altercationem (nominative altercatio) "a dispute, debate, discussion," noun of action from past participle stem of altercari "to dispute (with another)," from alter "other" (see alter).
alternate (adj.): 1510s, from Latin alternatus "one after the other," past participle of alternare "to do first one thing then the other; exchange parts," from alternus "one after the other, alternate, in turns, reciprocal," from alter "the other" (see alter). Alternate means "by turns;" alternative means "offering a choice." Both imply two kinds or things.
alternate (v.): 1590s, from Latin alternatus, past participle of alternare (see alternate (adj.)). Replaced Middle English alternen "to vary, alternate" (early 15c.). Related: Alternated; alternating.
alternate (n.): 1718, "that which alternates (with anything else)," from alternate (adj.). Meaning "a substitute" is first attested 1848.
alternately (adv.): early 15c., from alternate (adj.) + -ly (2).
alternating (adj.): 1550s, present participle adjective from alternate (v.). Alternating current is recorded from 1839.
alternation (n.): mid-15c., from Old French alternacion, from Latin alternationem (nominative alternatio), noun of action from past participle stem of alternare (see alternate (v.)).
alternative (adj.): 1580s, "offering one or the other of two," from Medieval Latin alternativus, from Latin alternatus, past participle of alternare (see alternate (v.)). Meaning "purporting to be a superior choice to what is in general use" was current by 1970 (earliest reference is to the media). Alternative energy is from 1975. Related: Alternatively.
alternative (n.): 1620s, in rhetoric, from Medieval Latin alternativus (see alternative (adj.)). Of courses of action, from 1814. Of objects, etc., "the other of two which may be chosen," by 1838.
alternator (n.): 1878, agent noun in Latin form from alternate (v.).
although (conj.): early 14c., althagh, compound of all + though, showing once-common emphatic use of all. "All though was originally more emphatic than though, but by 1400 it was practically only a variant of it, and all having thus lost its independent force, the phrase was written as one word" [OED].
altimeter (n.): 1918, from Modern Latin altimeter, from alti- "high" (from Latin altus; see old) + -meter.
altimetry (n.): 1690s, from Medieval Latin altimetria, from Latin alti- "high" (see old) + Greek -metria (see -metry).
altitude (n.): late 14c., from Latin altitudinem (nominative altitudo) "height, altitude," from altus "high" (see old).
alto (n.): 1784, "man with an alto voice," from Italian alto (canto), from Latin altus "high" (see old). Originally a "high" man's voice, now more commonly applied to the lower range of women's voices (which is more strictly the contralto), an extension first recorded in 1881.
The alto in a man is totally distinct from the contralto in a woman. The tone is utterly different -- the best notes of the one are certainly not the best notes of the other; and although in certain cases a contralto may sing with good effect music written for a male alto (e.g. in some oratorios), yet the converse is scarcely ever true. ["How to Sing," 1890]
As a type of saxophone, from 1869.
altogether: early 13c., altogedere, a strengthened form of all (also see together); used in the sense of "a whole" from 1660s. The altogether "nude" is from 1894.
altruism (n .): 1853, "unselfishness, opposite of egoism," from French altruisme, coined or popularized 1830 by French philosopher Auguste Comte (1798-1857), from autrui, from Old French altrui, "of or to others," from Latin alteri, dative of alter "other" (see alter). Apparently suggested to Comte by French legal phrase l'autrui, or in full, le bien, le droit d'autrui. The -l- is perhaps a reinsertion from the Latin word.
There is a fable that when the badger had been stung all over by bees, a bear consoled him by a rhapsodic account of how he himself had just breakfasted on their honey. The badger replied peevishly, "The stings are in my flesh, and the sweetness is on your muzzle." The bear, it is said, was surprised at the badger's want of altruism. ["George Eliot," "Theophrastus Such," 1879]
altruist (n.): 1842, from French; see altruism + -ist.
altruistic (adj.): 1853, from French altruiste (adj.), from altruisme (see altruism) + -ic.
alum (n.): late 14c., "whitish mineral salt used as an astringent, dye, etc.," from Old French alum, from Latin alumen "alum," literally "bitter salt," cognate with Greek aludoimos "bitter" and perhaps with English ale.
aluminium: see aluminum.
aluminum (n.): 1812, coined by English chemist Sir Humphry Davy (1778-1829), from alumina, name given 18c. to aluminum oxide, from Latin alumen "alum" (see alum). Davy originally called it alumium (1808), then amended this to aluminum, which remains the U.S. word, but British editors in 1812 further amended it to aluminium, the modern preferred British form, to better harmonize with other metallic element names (sodium, potassium, etc.).
Aluminium, for so we shall take the liberty of writing the word, in preference to aluminum, which has a less classical sound. ["Quarterly Review," 1812]