Online Etymology Dictionary

ban (v.): O.E. bannan "to summon, command, proclaim," from P.Gmc. *bannan "proclaim, command, forbid" (cf. O.H.G. bannan "to command or forbid under threat of punishment," Ger. bannen "banish, expel, curse"), originally "to speak publicly," from PIE base *bha- "to speak" (cf. O.Ir. bann "law," Armenian ban "word;" see fame). Main modern sense of "to prohibit" is from O.N. cognate banna "curse, prohibit," and probably in part from O.Fr. ban, which meant "outlawry, banishment," among other things (see banal) and was a borrowing from Germanic. The sense evolution in Germanic was from "speak" to "proclaim a threat" to (in O.N., Ger., etc.) "curse." The Germanic root, borrowed in Latin and French, has been productive: cf. banish, bandit, contraband, etc. Banned in Boston dates from 1920s, in allusion to the excessive zeal and power of that city's Watch and Ward Society.
ban (n.2): "governor of Croatia," from Serbo-Croat. ban "lord, master, ruler," from Pers. ban "prince, lord, chief, governor," related to Skt. pati "guards, protects." Hence banat "district governed by a ban," with Latinate suffix -atus. The Persian word got into Slavic perhaps via the Avars.
ban (n.1): "edict of prohibition," from ban (v.). O.E. (ge)bann meant "proclamation, summons, command."
banal: "trite, commonplace," 1840, from Fr. banal, adj., "belonging to a manor, common, hackneyed, commonplace," from O.Fr. banel "communal" (13c.), from ban "decree; legal control; announcement; authorization; payment for use of a communal oven, mill, etc." (see ban (v.)). The modern sense evolved from the word's use in designating things like ovens or mills that belonged to feudal serfs, or else compulsory military service; in either case it was generalized in French through "open to everyone" to "commonplace, ordinary," to "trite, petty."
banality: 1861, triteness, from Fr. banalité "banality, commonplace," from banal (see banal).
banana: 1590s, borrowed by Sp. or Port. from a W. African word, possibly Wolof banana. The plant introduced to the New World from Africa, 1516. Top banana, second banana, etc. are 1950s, from show business slang use of banana for "comedian, especially in a burlesque show." Banana split first attested 1920. Banana oil "nonsense" is slang from c.1910.
banana republic: "small Central American state with an economy dependent on banana production," 1935, Amer.Eng.
bananas: "crazy," 1968; earlier (1935) it was noted as an underworld slang term for "sexually perverted."
banausic: "merely mechanical," coined 1845 from Gk. banausikos "pertaining to mechanics," from banausos "artisan, mere mechanical," hence (to the Greeks) "base, ignoble;" perhaps lit. "working by fire," from baunos "furnace, forge" (but Klein dismisses this as folk etymology and calls it "of uncertain origin").
band (1): "a flat strip," also "something that binds," a merger of two words, ultimately from the same source. In the sense "that by which someone or something is bound," it is attested from 1126, from O.N. band "thin strip that ties or constrains," from P.Gmc. *bindan (related to Mod.Eng. bend and bind), from PIE *bendh- "to bind" (cf. Goth bandi "that which binds; Skt. bandhah "a tying, bandage," source of bandana; M.Ir. bainna "bracelet"). Most of the fig. senses of this word have passed into bond (q.v.), which originally was a phonetic variant of band. The meaning "a flat strip" (late 14c.) is from O.Fr. bande "strip, edge, side," via O.N.Fr. bende, from O.H.G. binda, from P.Gmc. *bindan (see above). In M.E., this was distinguished by the spelling bande, but since the loss of the final -e the words have fully merged. Meaning "broad stripe of color" is from 1470; the electronics sense of "range of frequencies or wavelengths" is from 1922. The O.N.Fr. form was retained in heraldic bend.
band (2): "an organized group," late 15c., from M.Fr. bande , traceable to P.Gmc. root of band (1), probably via a band of cloth worn as a mark of identification by a group of soldiers or others (cf. Gothic bandwa "a sign"). The extension to "group of musicians" is c.1660, originally musicians attached to a regiment of the army. To beat the band (1897) is to make enough noise to drown it out, hence to exceed everything.
Band-Aid: trademark registered 1924 by Johnson & Johnson for a stick-on gauze pad or strip. The British equivalent was Elastoplast. Fig. sense of "temporary or makeshift solution to a problem, pallative" (often lower case, sometimes bandaid) is first recorded 1968; as an adj., from 1970.
bandage: 1590s, from M.Fr. bandage (16c.), from O.Fr. bander "to bind," from bande "a strip" (see band (1)).
bandana: 1752, also often bandanna, from Hindi bandhnu a method of dyeing, from Skt. badhnati "binds" (because the cloth is tied like modern tie-dye), from same PIE root as band (1). The colors and spots are what makes it a bandana.
bandeau: 1706, from Fr. bandeau, from O.Fr. bandel (12c.), dim. of bande "band" (see band (1)).
bandicoot: 1789, from Telegu pandi-kokku, lit. "pig-rat." Properly a large and destructive Indian rat; applied from 1827 to a type of insectivorous Australian marsupial somewhat resembling it.
bandit: 1590s, from It. bandito (pl. banditi) "outlaw," pp. of bandire "proscribe, banish," from V.L. *bannire "to proclaim, proscribe," from P.Gmc. *bann (see ban). *Bannire (or its Frankish cognate *bannjan) in O.Fr. became banir-, which, with lengthened stem, became English banish.
bandolier: 1570s, "shoulder belt (for a wallet)," from Fr. bandouiliere (16c.), from It. bandoliera or Sp. bandolera, from dim. of banda "a scarf, sash," a Gmc. loan-word related to Goth. bandwa (see band (2)). In some cases, directly from Spanish to English as bandoleer. Meaning "ammunition belt for a musket" is from 1590s; hence bandolero "highwayman, robber" (1832), from Spanish, lit. "man who wears a bandoleer."
bandwagon: 1855, Amer.Eng., from band (2) + wagon, originally a large wagon used to carry the band in a circus procession; as these also figured in celebrations of successful political campaigns, being on the bandwagon came to represent "attaching oneself to anything that looks likely to succeed," a usage first attested 1899 in writings of Theodore Roosevelt.
bandwidth: 1930, in electronics, from band (1) + width.
bandy (v.): 1570s, "to strike back and forth," from M.Fr. bander, from root of band (2). The sense apparently evolved from "join together to oppose," to opposition itself, to "exchanging blows," then metaphorically, to volleying in tennis. Bandy was a 17c. Irish game, precursor of field hockey, played with curved a stick (also called a bandy), hence bandy-legged (1680s).
bane: O.E. bana "killer, slayer, murderer," from P.Gmc. *banon, cognate with *banja- "wound" (cf. O.Fris. bona "murderer," O.H.G. bana "murder," O.E. benn "wound," Goth. banja "stroke, wound"), from PIE base *gwhen- "to strike, kill, wound" (cf. Avestan banta "ill"). Modern sense of "that which causes ruin or woe" is from 1570s.
bang: 1540s, "to strike hard with a loud blow," from O.N. banga "to pound, hammer" of echoic origin. Slang meaning "have sexual intercourse with" first recorded 1937. Bang-up "excellent, first-rate," 1820, probably shortened from phrase bang up to the mark.
"This is the way the world ends
Not with a bang but a whimper"

[T.S. Eliot, "Hollow Men," 1925]
banger: British slang for "a sausage," 1919, perhaps from sense of "a bludgeon," though this is recorded only in U.S. slang.
Bangladesh: nation formed 1971 from former East Pakistan, from Bengali for "Bengali country," from Bangla "Bengali" + desh "country."
bangle: "ring-shaped bracelet," 1787, from Hindi bangri "colored glass bracelet or anklet."
bangs: "hair cut straight across the forehead," 1878 (sing.), Amer.Eng., 1870 of horses (bang-tail), perhaps from notion of abruptness (cf. bang off "immediately, without delay," though this expression is attested only from 1886). See bang.
banish: early 14c., banischen, from banniss-, extended stem of O.Fr. banir "announce, proclaim; levy; forbid; banish, proclaim an outlaw," from Frankish *bannjan "to order or prohibit under penalty," or from V.L. cognate *bannire (see bandit). Related: Banishment (c.1500).
banister: 1660s, unexplained corruption of baluster. As late as 1830 condemned as "vulgar," it is now accepted.
banjo: 1764, Amer.Eng., usually described as of African origin, probably akin to Bantu mbanza, an instrument resembling a banjo. The word has been influenced by colloquial pronunciation of bandore (1560s in English), a 16c. stringed instrument like a lute and an ancestor (musically and linguistically) of mandolin; from Port. bandurra, from L. pandura, from Gk. pandoura "three-stringed instrument." The origin and influence might be the reverse of what is here described.
bank (1): "financial institution," late 15c., from either O.It. banca or M.Fr. banque (itself from the O.It. word), both meaning "table" (the notion is of the moneylender's exchange table), from a Gmc. source (cf. O.H.G. bank "bench"); see bank (2). The verb meaning "to put confidence in" (U.S. colloquial) is attested from 1884. Bank holiday is from 1871, though the tradition is as old as the Bank of England. To cry all the way to the bank was coined 1956 by flamboyant pianist Liberace, after a Madison Square Garden concert that was packed with patrons but panned by critics.
bank (2): "earthen incline, edge of a river," c.1200, probably in O.E. but not attested in surviving documents, from a Scandinavian source such as O.N. banki, O.Dan. banke "sandbank," from P.Gmc. *bangkon "slope," cognate with *bankiz "shelf."
banker: 1530s, formed from bank (1), possibly modeled on Fr. banquier (16c.).
bankroll (n.): 1887, from bank (1) + roll (n.). The verb is attested from 1928.
bankrupt: 1530s, from It. banca rotta, lit. "a broken bench," from banca "moneylender's shop," lit. "bench" (see bank (1)) + rotta "broken, defeated, interrupted" from (and remodeled on) L. rupta, fem. pp. of rumpere "to break" (see rupture). "[S]o called from the habit of breaking the bench of bankrupts" [Klein]. The verb is first recorded 1550s.
bankruptcy: 1700, from bankrupt, "probably on the analogy of insolvency, but with -t erroneously retained in spelling, instead of being merged in the suffix ...." [OED].
bann: in phrase banns of marriage (late 12c., spelling with double -n- attested from 1540s), from O.E.bannan "to summon, command, proclaim" (see ban (v.)). Also probably partly from O.Fr. ban "announcement, proclamation, banns, authorization," from Frankish *ban, a cognate of the O.E. word.
banner: early 13c., from O.Fr. baniere (Mod.Fr. bannière) "flag, banner, standard," from L.L. bandum "standard," borrowed from a W.Gmc. cognate of Goth. bandwa "a sign" (see band (2)). Of newspaper headlines, from 1913.
banneret: late 13c., an order of knighthood, originally in reference to one who could lead his men into battle under his own banner. Later it meant one who received rank for valiant deeds done in the king's presence in battle.
bannock: "thick flat cake," O.E. bannuc "a bit, small piece," from Gael. bannach "a cake," perhaps a loan from L. panis "bread" (see food).
banns: see bann.
banquet: late 15c., from Fr. banquet (15c.; in O.Fr. only "small bench"), from O.It. banchetto, dim. of banco "bench;" originally a snack eaten on a bench (rather than at table), hence "a slight repast between meals;" the meaning has entirely reversed.
banquette: 1620s, "raised platform in a fortification," from Fr. banquette (15c.), from It. banchetta, dim. of banca "bench, shelf" (see bank (1)).
banshee: 1771, from phonetic spelling of Ir. bean sidhe "female of the Elves," from bean "woman" (from PIE span class="foreign">*gwen-; see queen) + sidhe, from sith "fairy" or sid "fairy mound." Specifically, one who calls to the spirits of the dead.
bantam: 1749, after Bantam, former Dutch residency in Java, from which the small domestic fowl were said to have been first imported. Extension to "small person" is 1837. As a light weight class in boxing, it is attested from 1884, probably from the birds, which are small but aggressive and bred for fighting.
banter: 1670s, slang, origin uncertain.
banting: system for weight loss through diet control, named for William Banting (1797–1878), English undertaker who invented it, tested it himself, and promoted it in his 1863 booklet "Letter on Corpulence, Addressed to the Public." Although the word is a surname, it was used like a verbal noun in -ing. ("She is banting").
Bantu: 1862, applied to south African language group by W.H.I. Bleek, from native Ba-ntu "mankind," from ba-, plural prefix + ntu "a man, person."
banyan: "Indian fig tree," 1630s, so called in allusion to a tree on the Iranian coast of the Persian Gulf under which the Hindu merchants known as banians had built a pagoda. From Skt. vanija "merchant."
banzai: Japanese war-cry, 1893, lit. "(may you live) ten thousand years," originally a greeting addressed to the emperor, from ban "ten thousand" + sai "year."