bold (adj.)youdaoicibaDictYouDict[bold 词源字典]
Old English beald (West Saxon), bald (Anglian) "bold, brave, confident, strong," from Proto-Germanic *balthaz (cognates: Old High German bald "bold, swift," in names such as Archibald, Leopold, Theobald; Gothic balþei "boldness;" Old Norse ballr "frightful, dangerous"), perhaps from PIE *bhol-to- suffixed form of *bhel- (2) "to blow, swell" (see bole).

Of flavors (coffee, etc.) from 1829. The noun meaning "those who are bold" is from c. 1300. Old French and Provençal baut "bold," Italian baldo "bold, daring, fearless" are Germanic loan-words.[bold etymology, bold origin, 英语词源]
bold-face (n.)youdaoicibaDictYouDict
in typography, 1845, from bold (adj.) + face (n.). In reference to types, bold (adj.) is attested from 1790, perhaps from the secondary sense "easily visible, striking to the eye."
bole (n.)youdaoicibaDictYouDict
early 14c., from Old Norse bolr "tree trunk," from Proto-Germanic *bulas (cognates: Middle Dutch bolle "trunk of a tree"), from PIE *bhel- (2) "to blow, inflate, swell" (cognates: Greek phyllon "leaf," phallos "swollen penis;" Latin flos "flower," florere "to blossom, flourish," folium "leaf;" Old Prussian balsinis "cushion;" Old Norse belgr "bag, bellows;" Old English bolla "pot, cup, bowl;" Old Irish bolgaim "I swell," blath "blossom, flower," bolach "pimple," bolg "bag;" Breton bolc'h "flax pod;" Serbian buljiti "to stare, be bug-eyed;" Serbo-Croatian blazina "pillow").
bolero (n.)youdaoicibaDictYouDict
kind of Spanish dance, 1787, from Spanish, probably from bola "ball" (and perhaps with reference to "whirling motion"), from Latin bulla (see bull (n.2)). In reference to a type of short jacket, it is recorded by 1864.
BoliviayoudaoicibaDictYouDict
South American republic, founded 1825, named for Simon Bolivar (1783-1830), statesman and soldier.
boll (n.)youdaoicibaDictYouDict
Old English bolla "bowl, cup, pot," merged with Middle Dutch bolle "round object," borrowed 13c., both from Proto-Germanic *bul-, from PIE *bhel- (2) "to blow, inflate, swell" (see bole). Influenced in meaning by Latin bulla "bubble, ball," ultimately from the same PIE root. Extended c. 1500 to "round seed pod of flax or cotton." Boll weevil is 1895, American English.
In south Texas, among Spanish-speaking people, the insect is generally known as the 'picudo,' a descriptive name which refers to the snout or beak of the insect. English-speaking planters generally referred to the insect at first as 'the sharpshooter,' a term which for many years has been applied to any insect which causes through its punctures the shedding of the squares or the rotting of the bolls. As there are several native insects that are commonly called sharpshooters and which, though injurious, are by no means to be compared with this insect, it becomes necessary to discourage in every way the use of the word sharpshooter as applied to this weevil. The adoption of the term 'Mexican cotton-boll weevil' for the new pest is recommended. [New Mexico College of Agriculture and the Mechanic Arts Agricultural Experiment Station Bulletin No. 19, April 1896]
A case of entomology meddling in etymology.
bollard (n.)youdaoicibaDictYouDict
1844, originally a post for fixing mooring ropes; since 1948, usually a traffic control device; probably from bole + suffix -ard.
bollix (v.)youdaoicibaDictYouDict
"bungle," respelling (perhaps euphemistic) of bollocks, plural of bollock "testicle," from Old English beallucas "testicles," from Proto-Germanic *ball-, from PIE *bhel- (2) "to inflate, swell" (see bole). Related: Bollixed; bollixing.
bollock (n.)youdaoicibaDictYouDict
singular of bollocks (q.v.).
bollocks (n.)youdaoicibaDictYouDict
"testicles," 1744, see bollix. In British slang, as an ejaculation meaning "nonsense," recorded from 1919.
BollywoodyoudaoicibaDictYouDict
"film industry based in Mumbai, India," 1977, from Bombay (old name of Mumbai) + Hollywood.
Bolo (n.)youdaoicibaDictYouDict
"traitor," 1917, from Paul Bolo, French adventurer shot for treason April 17, 1918; used in World War I with reference to pacifist propagandists; later somewhat assimilated to Bolshevik (q.v.).
bologna (n.)youdaoicibaDictYouDict
1850, variant of bologna sausage (1590s), named for the city in Italy, whose name is from Latin Bononia, which either represents Gaulish bona "foundation, fortress," or Boii, the name of the Gaulish people who occupied the region 4c. B.C.E. Also see baloney.
Bolognese (adj.)youdaoicibaDictYouDict
1756, pertaining to Bologna (q.v.).
boloney (n.)youdaoicibaDictYouDict
see baloney.
Bolshevik (n.)youdaoicibaDictYouDict
1917, from Russian bol'shiy "greater," comparative of adjective bol'shoy "big, great" (as in Bolshoi Ballet), from Old Church Slavonic boljiji "larger," from PIE root *bel- "strong" (cognates: Sanskrit balam "strength, force," Greek beltion "better," Phrygian balaios "big, fast," Old Irish odbal "strong," Welsh balch "proud;" Middle Dutch, Low German, Frisian pal "strong, firm").

It was the faction of the Russian Social Democratic Worker's Party after a split in 1903 that was either larger or more extreme (or both) than the Mensheviks (from Russian men'shij "less"); after they seized power in 1917, applied generally to Russian communists. Bolshevism is recorded from 1917.
bolster (v.)youdaoicibaDictYouDict
mid-15c. (implied in bolstered), "propped up, made to bulge" (originally of a woman's breasts), from bolster (n.). Figurative sense is from c. 1500, on the notion of "to support with a bolster, prop up." Related: Bolstering.
bolster (n.)youdaoicibaDictYouDict
Old English bolster "bolster, cushion, something stuffed so that it swells up," especially "long, stuffed pillow," from Proto-Germanic *bolkhstraz (cognates: Old Norse bolstr, Danish, Swedish, Dutch bolster, German polster), from PIE *bhelgh- "to swell" (see belly (n.)).
bolt (n.)youdaoicibaDictYouDict
Old English bolt "short, stout arrow with a heavy head;" also "crossbow for throwing bolts," from Proto-Germanic *bultas (cognates: Old Norse bolti, Danish bolt, Dutch bout, German Bolzen), perhaps from PIE root *bheld- "to knock, strike" (cognates: Lithuanian beldu "I knock," baldas "pole for striking").

Applied since Middle English to other short metal rods (especially those with knobbed ends). From the notion of an arrow's flight comes the lightning bolt (1530s). A bolt of canvas (c. 1400) was so called for its shape. Adverbial phrase bolt upright is from late 14c.
bolt (v.)youdaoicibaDictYouDict
from bolt (n.) in its various senses; from a crossbow arrow's quick flight comes the meaning "to spring, to make a quick start" (early 13c.). Via the notion of runaway horses, this came to mean "to leave suddenly" (early 19c.). Meaning "to gulp down food" is from 1794. The meaning "to secure by means of a bolt" is from 1580s. Related: Bolted; bolting.