busk (v.) Look up busk at Dictionary.com
"to prepare, to dress oneself," also "to go, set out," c. 1300, probably from Old Norse buask "to prepare oneself," reflexive of bua "to prepare" (see bound (adj.2)) + contraction of Old Norse reflexive pronoun sik. Most common in northern Middle English and surviving chiefly in Scottish and northern English dialect. Related boun had the same senses in northern and Scottish Middle English. Related: Busked; busking.

The nautical term is attested from 1660s (in a general sense of "to tack, to beat to windward"), apparently from obsolete French busquer "to shift, filch, prowl," which is related to Italian buscare "to filch, prowl," Spanish buscar (from Old Spanish boscar), perhaps originally from bosco "wood" (see bush (n.)), with a hunting notion of "beating a wood" to flush game.
busk (n.) Look up busk (n.) at Dictionary.com
"strip of wood, whalebone, etc., used in corset-making," 1590s, probably from French busc (16c.), from Italian bosco "splinter," of Germanic origin (see bush (n.)).
busker (n.) Look up busker at Dictionary.com
"itinerant entertainer," 1857, from busk (v.) "to offer goods for sale only in bars and taprooms," 1851 (in Mayhew), perhaps from busk "to cruise as a pirate," which was used in a figurative sense by 1841, in reference to people living shiftless and peripatetic lives. Busker has been mistakenly derived from buskin in the stage sense.
buskin (n.) Look up buskin at Dictionary.com
"half boot," c. 1500, origin unknown. The word exists in different forms in most of the continental languages, and the exact relationship of them all apparently has yet to be determined. The English word is perhaps immediately from Old French broissequin "buskin; a kind of cloth" (14c., Modern French brodequin by influence of broder "to embroider"), or from Middle Dutch brosekin "small leather boot," which is of uncertain origin. OED suggests a likely candidate in Spanish borcegui, earlier boszegui

Figurative senses in English relating to tragedy are from the word being used (since mid-16c.) to translate Greek kothurnus, the high, thick-soled boot worn in Athenian tragedy; contrasted with sock, the low shoe worn by comedians. Related: Buskined.
busking (n.) Look up busking at Dictionary.com
1851, slang, described variously as selling articles or obscene ballads in public houses, playing music on the streets, or performing as a sort of informal stand-up comedy act in pubs, perhaps from an earlier word meaning "to cruise as a pirate" (see busker).
buss (v.) Look up buss at Dictionary.com
1570s, from buss (n.). Related: Bussed; bussing.
Kissing and bussing differ both in this,
We busse our wantons, but our wives we kisse.

[Robert Herrick, "Hesperides," 1648]
buss (n.) Look up buss at Dictionary.com
"a kiss," 1560s; probably of imitative origin, as are Welsh and Gaelic bus "kiss, lip," French baiser "kiss" (12c., from Latin basiare), Spanish buz, German dialectal Buss.
bussing (n.) Look up bussing at Dictionary.com
"kissing," 1888, verbal noun from buss (v.).
bust (n.1) Look up bust at Dictionary.com
1690s, "sculpture of upper torso and head," from French buste (16c.), from Italian busto "upper body," from Latin bustum "funeral monument, tomb," originally "funeral pyre, place where corpses are burned," perhaps shortened from ambustum, neuter of ambustus "burned around," past participle of amburere "burn around, scorch," from ambi- "around" + urere "to burn." Or perhaps from Old Latin boro, the early form of classical Latin uro "to burn." Sense development in Italian is probably from Etruscan custom of keeping dead person's ashes in an urn shaped like the person when alive. Meaning "bosom" is by 1884.
bust (n.2) Look up bust at Dictionary.com
variant of burst (n.), 1764, American English. For loss of -r-, compare ass (n.2). Originally "frolic, spree;" sense of "sudden failure" is from 1842. Meaning "police raid or arrest" is from 1938. Phrase ______ or bust as an emphatic expression attested by 1851 in British depictions of Western U.S. dialect. Probably from earlier expression bust (one's) boiler, by late 1840s, a reference to steamboat boilers exploding when driven too hard.
bust (v.) Look up bust at Dictionary.com
"to burst," 1806, variant of burst (v.); for loss of -r-, compare ass (n.2). Meaning "go bankrupt" is from 1834. Meaning "break into" is from 1859. The slang meaning "demote" (especially in a military sense) is from 1918; that of "place under arrest" is from 1953 (earlier "to raid" from Prohibition). In card games, "to go over a score of 21," from 1939. Related: Busted; busting.
bustard (n.) Look up bustard at Dictionary.com
large crane-like bird, mid-15c. (late 14c. as a surname), from Old French bistarde, said to be from Latin avis tarda, but the sense of this ("slow bird") is the opposite of the bird's behavior.
busted (adj.) Look up busted at Dictionary.com
"broken, ruined," 1837, past participle adjective from bust (v.).
buster (n.) Look up buster at Dictionary.com
1838, "anything large; a man of great strength," American English slang (originally Missouri/Arkansas), perhaps meaning something that takes one's breath away and an agent noun from bust (v.). Around the same years, buster (as an extended form of bust (n.)) also meant "a frolic, a spree." Hence "a roistering blade" (OED; probably not the favored definition in old Missouri and Arkansas), attested from 1850. As a generic or playful address to a male, from 1948, American English. Meaning "horse-breaker" is from 1891, American English; hence back-formed verb bust (v.) "break a horse."
bustier (n.) Look up bustier at Dictionary.com
1979, from French bustier, from buste "bust" (see bust (n.1)).
bustle (n.1) Look up bustle at Dictionary.com
"activity, stir, fuss, commotion," 1630s, from bustle (v.).
bustle (v.) Look up bustle at Dictionary.com
"be active," 1570s (bustling "noisy or excited activity" is from early 15c.), frequentative of Middle English bresten "to rush, break," from Old English bersten (see burst (v.)), influenced by Old Norse buask "to make oneself ready" (see busk (v.)), or it might be from busk (v.) via a frequentative form buskle. Related: Bustled; bustling; bustler.
bustle (n.2) Look up bustle at Dictionary.com
"padding in a skirt," 1788, of uncertain origin, perhaps from German Buschel "bunch, pad," or it might be a special use of bustle (n.1) with reference to "rustling motion."
BUSTLE. A pad stuffed with cotton, feathers, bran, &c., worn by ladies for the double purpose of giving a greater rotundity or prominence to the hips, and setting off the smallness of the waist. [Bartlett, "Dictionary of Americanisms," 1848]
bustling (adj.) Look up bustling at Dictionary.com
of a place, 1880, present participle adjective from bustle (v.).
busty (adj.) Look up busty at Dictionary.com
"having large breasts," 1944, from bust (n.1) in the "bosom" sense + -y (2). Related: Bustiness.
busy (v.) Look up busy at Dictionary.com
late Old English bisgian, from busy (adj.). Related: Busied; busying.
busy (adj.) Look up busy at Dictionary.com
Old English bisig "careful, anxious," later "continually employed or occupied," cognate with Old Dutch bezich, Low German besig; no known connection with any other Germanic or Indo-European language. Still pronounced as in Middle English, but for some unclear reason the spelling shifted to -u- in 15c.

The notion of "anxiousness" has drained from the word since Middle English. Often in a bad sense in early Modern English, "prying, meddlesome" (preserved in busybody). The word was a euphemism for "sexually active" in 17c. Of telephone lines, 1893. Of display work, "excessively detailed, visually cluttered," 1903.
busy-work (n.) Look up busy-work at Dictionary.com
also busy work, 1910, from busy (adj.) + work (n.).
busybody (n.) Look up busybody at Dictionary.com
"meddlesome person," 1520s, from busy (adj.) in the otherwise-obsolete sense "prying, meddlesome" + body "person."
busyness (n.) Look up busyness at Dictionary.com
1849, first attested in Thoreau, from busy (adj.) + -ness. A modern formation made necessary after business evolved away from busy.
but (adv., prep.) Look up but at Dictionary.com
Old English butan, buton "unless, except; without, outside," from West Germanic *be-utan, a compound of *be- "by" (see by) + *utana "out, outside; from without," from ut "out" (see out (adv.)). Not used as a conjunction in Old English. As a noun from late 14c.
butane (n.) Look up butane at Dictionary.com
paraffin hydrocarbon, 1875, from butyl, hydrocarbon from butyric acid, a product of fermentation found in rancid butter, from Latin butyrum (see butter (n.)) + chemical suffix -ane.
butch (n.) Look up butch at Dictionary.com
"tough youth," 1902, first attested in nickname of U.S. outlaw George Cassidy (1866-?), probably an abbreviation of butcher (n.). Sense of "aggressive lesbian" is 1940s.
butcher (v.) Look up butcher at Dictionary.com
1560s, from butcher (n.). Related: Butchered; butchering. Re-nouned 1640s as butcherer.
butcher (n.) Look up butcher at Dictionary.com
c. 1300, from Anglo-French boucher, from Old French bochier "butcher, executioner" (12c., Modern French boucher), probably literally "slaughterer of goats," from bouc "male goat," from Frankish *bukk or some other Germanic source (see buck (n.1)) or Celtic *bukkos "he-goat." Figurative sense of "brutal murderer" is attested from 1520s. Butcher-knife attested from 18c. Related: Butcherly. Old English had flæscmangere "butcher" ('flesh-monger').
butchery (n.) Look up butchery at Dictionary.com
"the trade of a butcher," mid-15c., bocherie, from Old French bocherie (13c., Modern French boucherie), from bochier (see butcher (n.)).
butler (n.) Look up butler at Dictionary.com
late 12c., from Anglo-French buteillier "cup-bearer," from Old French boteillier "cup-bearer, butler, officer in charge of wine," from boteille "wine vessel, bottle" (see bottle (n.)). The word reflects the position's original function as "chief servant in charge of wine." In Old French, fem. boteilliere was used of the Virgin Mary as "dispenser" of the cup of Mercy.
butt (n.4) Look up butt at Dictionary.com
"flat fish," c. 1300, a general Germanic name applied to various kinds of flat fishes; compare Old Swedish but "flatfish," German Butte, Dutch bot, perhaps ultimately related to butt (n.1). "Hence butt-woman, who sells these, a fish-wife." [OED]
butt (n.1) Look up butt at Dictionary.com
"thick end," c. 1400, butte, which probably is related to Middle Dutch and Dutch bot, Low German butt "blunt, dull," Old Norse bauta (see beat (v.)). Or related somehow to Old English buttuc "end, small piece of land," and Old Norse butr "short." In sense of "human posterior" it is recorded from mid-15c. Meaning "remainder of a smoked cigarette" first recorded 1847.
butt (n.3) Look up butt at Dictionary.com
"target of a joke," 1610s, originally "target for shooting practice" (mid-14c.), from Old French but "aim, goal, end, target (of an arrow, etc.)," 13c., which seems to be a fusion of Old French words for "end" (bout) and "aim, goal" (but), both ultimately from Germanic. The latter is from Frankish *but "stump, stock, block," or some other Germanic source (compare Old Norse butr "log of wood"), which would connect it with butt (n.1).
butt (v.) Look up butt at Dictionary.com
"hit with the head," c. 1200, from Anglo-French buter, from Old French boter "to push, shove, knock; to thrust against," from Frankish or another Germanic source (compare Old Norse bauta, Low German boten "to strike, beat"), from Proto-Germanic *butan, from PIE root *bhau- "to strike" (see batter (v.)). Related: Butted; butting. To butt in "rudely intrude" is American English, attested from 1900.
butt (n.2) Look up butt at Dictionary.com
"liquor barrel," late 14c., from Anglo-French but and Old French bot "barrel, wine-skin" (14c., Modern French botte), from Late Latin buttis "cask" (see bottle (n.)). Cognate with Spanish and Portuguese bota, Italian botte. Usually a cask holding 108 to 140 gallons, or roughly two hogsheads, but the measure varied greatly.
butte (n.) Look up butte at Dictionary.com
1805, American English, from French butte, from Old French but "mound, knoll" (see butt (n.3)). A French word introduced in Lewis & Clark's journals.
butter (v.) Look up butter at Dictionary.com
Old English buterian "spread butter on," from the same source as butter (n.). Figurative meaning "to flatter lavishly" is by 1798 (with up (adv.), in Connelly's Spanish-English dictionary, p.413). Related: Buttered; buttering.
butter (n.) Look up butter at Dictionary.com
Old English butere "butter," general West Germanic (compare Old Frisian, Old High German butera, German Butter, Dutch boter), an early loan-word from Latin butyrum "butter" (source of Italian burro, Old French burre, French beurre), from Greek boutyron, perhaps literally "cow-cheese," from bous "ox, cow" (see cow (n.)) + tyros "cheese" (see tyrosine); but this might be a folk etymology of a Scythian word.

The product was used from an early date in India, Iran and northern Europe, but not in ancient Greece and Rome. Herodotus described it (along with cannabis) among the oddities of the Scythians. Butter-knife attested from 1818.
butter-fingered (adj.) Look up butter-fingered at Dictionary.com
"apt to let things fall," 1610s, from butter (n.) + finger (n.).
buttercup (n.) Look up buttercup at Dictionary.com
type of small wildflower with a yellow bloom, 1777, from a merger of two older names, gold-cups and butterflower. See butter (n.) + cup (n.).
butterfingers (n.) Look up butterfingers at Dictionary.com
"person apt to let things fall," 1837; see butter-fingered.
butterfly (n.) Look up butterfly at Dictionary.com
Old English buttorfleoge, evidently butter (n.) + fly (n.), but of obscure signification. Perhaps based on the old notion that the insects (or witches disguised as butterflies) consume butter or milk that is left uncovered. Or, less creatively, simply because the pale yellow color of many species' wings suggests the color of butter. Another theory connects it to the color of the insect's excrement, based on Dutch cognate boterschijte. An overview of words for "butterfly" in various languages can be found here. Also see papillon.

Applied to persons from c. 1600, originally in reference to vain and gaudy attire; by 1806 in reference to transformation from early lowly state; in reference to flitting tendencies by 1873. The swimming stroke so called from 1936. Butterflies "light stomach spasms caused by anxiety" is from 1908.
The butterfly effect is a deceptively simple insight extracted from a complex modern field. As a low-profile assistant professor in MIT's department of meteorology in 1961, [Edward] Lorenz created an early computer program to simulate weather. One day he changed one of a dozen numbers representing atmospheric conditions, from .506127 to .506. That tiny alteration utterly transformed his long-term forecast, a point Lorenz amplified in his 1972 paper, "Predictability: Does the Flap of a Butterfly's Wings in Brazil Set Off a Tornado in Texas?" [Peter Dizikes, "The Meaning of the Butterfly," The Boston Globe, June 8, 2008]
buttermilk (n.) Look up buttermilk at Dictionary.com
1520s, from butter (n.) + milk (n.). Compare German Buttermilch. It is what remains after the butter has been churned out.
butternut (n.) Look up butternut at Dictionary.com
also butter-nut, 1753, nut of the white walnut, a North American tree; transferred to the tree itself from 1783. The nut's color was a brownish-gray, hence the word was used (1861) to describe the warm gray color of the Southern army uniforms in the American Civil War.
buttery (adj.) Look up buttery at Dictionary.com
"resembling butter," late 14c., from butter (n.) + -y (2). Related: Butteriness.
buttery (n.) Look up buttery at Dictionary.com
"place for storing liquor," originally "room where provisions are laid up" (late 14c.), from Old French boterie, from Late Latin botaria, from bota, variant of butta "cask, bottle;" see butt (n.2) + -ery.
butthead (n.) Look up butthead at Dictionary.com
also butt-head, late 1980s, student slang, "objectionable person," from butt (n.1) + head (n.); perhaps influenced by butterhead, 1960s African-American vernacular for one who is a disgrace to the community. Earlier, butthead meant simply "the butt end, bottom" of anything (1630s).
butthole (n.) Look up butthole at Dictionary.com
also butt-hole, "anus," 1950s slang, from butt (n.1) + hole (n.). Earlier it meant "blind hole; cul-de-sac" (early 20c.).