"best," 1762, from better (adj.) + -most.
betting (n.)
"the making of wagers," 1590s, verbal noun bet (v.).
bettor (n.)
"one who lays a wager," c. 1600, also better, agent noun from bet (v.). The form is unusual; OED notes that English agent nouns in -er tend to shift toward -or as their senses become more specific; in this case it also could be to avoid confusion with better (n.1).
fem. pet name, from Bet, shortened from Elizabeth, + -y (3). Also in old slang (by 1857), "man who interferes with the domestic duties of women" [Century Dictionary, 1889].
Betula (n.)
genus of the birches, from Latin betula "birch," from Gaulish betu- "bitumen" (source also of Middle Irish beithe "box tree," Welsh bedwen "birch tree"). According to Pliny, so called because the Gauls extracted tar from birches. Birch tar still is sold as an analgesic and stimulant and made into birch beer by the Pennsylvania Dutch.
between (prep., adv.)
Old English betweonum, Mercian betwinum, "in the space which separates, midway, in the midst, among; by turns," from bi- "by" (see by) + tweonum dative plural of *tweon "two each" (compare Gothic tweih-nai "two each;" from PIE root *dwo- "two").
Between is literally applicable only to two objects; but it may be and commonly is used of more than two where they are spoken of distributively, or so that they can be thought of as divided into two parts or categories, or with reference to the action or being of each individually as compared with that of any other or all the others. When more than two objects are spoken of collectively or in divisibly, among is the proper word. [Century Dictionary]

In all senses, between has been from its earliest appearance, extended to more than two [OED].
Between a rock and a hard place is from 1940s, originally cowboy slang (earlier was between the beetle (hammer) and the block, late 19c.). Between-whiles "at intervals" is from 1670s.
betweenity (n.)
"state or condition of being between," 1760, a jocular formation, perhaps coined by Horace Walpole, from between + -ity.
betweenness (n.)
1881, from between + -ness.
betwixt (prep., adv.)
Old English betweox "between, in the space that separates, among, amidst, meanwhile," from bi- "by" (see by) + tweox "for two," from Proto-Germanic *twa "two" (from PIE root *dwo- "two") + *-isk "-ish." With unetymological -t that first appeared in Old English and became general after c. 1500. Compare amidst. Betwixen also was a variant in Old and Middle English.
fem. proper name, from Hebrew be'ulah "married woman," fem. past participle of ba'al "he married" (see baal).
bevel (adj.)
1560s, "having equal alternate angles;" c. 1600, "sloping from the horizontal or vertical," possibly from Old French *baivel (Modern French béveau, biveau), which is perhaps from bayer "to gape, yawn," from Latin *batare "to yawn, gape," possibly imitative of yawning. But if so, the time gap is puzzling.

As a noun from 1610s, "tool or instrument for drawing angles and adjusting abutting surfaces;" 1670s as "an angle between adjacent sides." The verb, "to reduce to a sloping edge," is first recorded 1670s. Related: Bevelled; bevelling.
bever (n.)
"drink," mid-15c.; "snack between meals," c. 1500, from Anglo-French beivre, Old French bevre, boivre, infinitive used as a noun, from Latin bibere "to imbibe" (from PIE root *po(i)- "to drink").
beverage (n.)
"drink of any kind," mid-13c., from Anglo-French beverage, Old French bevrage, from Old French boivre "to drink" (Modern French boire; from Latin bibere "to imbibe;" from PIE root *po(i)- "to drink") + -age, suffix forming mass or abstract nouns (see -age).
Beverly Hills
city in southern California, U.S., 1911, earlier Beverly (1907), named for Beverly Farms, Massachusetts, summer home of then-U.S. President Taft, which ultimately is named for the Yorkshire town Beverly, which means, in Old English, "beaver lodge."
bevy (n.)
early 15c., collective noun of quails and ladies, from Anglo-French bevée, which is of unknown origin. One supposed definition of the word is "a drinking bout," but this perhaps is a misprint of bever (see beverage). If not, perhaps the original sense is birds gathered at a puddle or pool for drinking or bathing. But the quest for a clear and logical origin in such a word might be futile. "These old names for companies of men and animals are however very fantastical and far-fetched" [OED].
bewail (v.)
"to mourn aloud," c. 1300, from be- + wail (v.). Related: Bewailed; bewailing.
beware (v.)
"be on one's guard," c. 1200, probably a contraction of be ware "be wary, be careful," from Middle English ware (adj.), from Old English wær "prudent, aware, alert, wary," from Proto-Germanic *waraz, from PIE root *wer- (3) "perceive, watch out for." Old English had the compound bewarian "to defend," which perhaps contributed to the word. Compare begone.
beweep (v.)
Old English bewepan "to weep over," cognate with Old Frisian biwepa, Old Saxon biwopian; see be- + weep. Related: Bewept.
bewigged (adj.)
1774, from be- + wig (n.).
bewilder (v.)
1680s, "confuse as to direction or situation," also, figuratively, "perplex, puzzle, confuse," from be- "thoroughly" + archaic wilder "lead astray, lure into the wilds," which is probably a back-formation from wilderness. An earlier word with the same sense was bewhape (early 14c.) and there is a 17c. use of bewhatle.
bewildered (adj.)
1680s, past participle adjective from bewilder (q.v.). Related: Bewilderedness.
bewildering (adj.)
1761, present-participle adjective from bewilder. Related: Bewilderingly.
bewilderment (n.)
1789, "state or condition of being bewildered," from bewilder + -ment; meaning "thing or situation which bewilders" is from 1840.
bewitch (v.)
c. 1200, biwicchen, "cast a spell on; enchant, subject to sorcery," from be- + Old English wiccian "to enchant, to practice witchcraft" (see witch). Literal at first, and with implication of harm; figurative sense of "to fascinate, charm past resistance" is from 1520s. *Bewiccian may well have existed in Old English, but it is not attested. Related: Bewitchery; bewitchment.
bewitched (adj.)
late 14c. in the literal sense, past participle adjective from bewitch; figurative use from 1570s.
bewitching (adj.)
"having the power to fascinate or charm," 1560s, present-participle adjective from bewitch (v.). Related: Bewitchingly.
bewray (v.)
early 13c., biwreien, "to inform against;" mid-13c., "to speak ill of," from be- + Middle English wreien "betray," from Old English wregan "accuse" (cognate with Old Saxon wrogian, Dutch wroegen "accuse," Old High German ruogen, German rügen "to censure," Gothic wrohjan "accuse"). Perhaps somewhat influenced in sense by unrelated betray. Sense of "to reveal, expose" is from late 14c. "Probably more or less of a conscious archaism since the 17th c." [OED]. Related: Bewrayed; bewraying; bewrayment.
bey (n.)
"governor of a Turkish district," 1590s, from Turkish bey, a title of honor in princely families, the Osmanli equivalent of Turkish beg, which is cognate with Persian baig "a lord."
beyond (prep., adv.)
Old English begeondan "on the other side of, from the farther side," from be- "by," here probably indicating position, + geond "yonder" (prep.); see yond. A compound not found elsewhere in Germanic. From late 14c. as "further on than," 1530s as "out of reach of." To be beyond (someone) "to pass (someone's) comprehension" is by 1812.
bezant (n.)
gold coin issued by the emperors at Constantinople, c. 1200, from Old French besant (12c.), from Latin byzantius, short for Byzantius nummus "coin of Byzantium." They circulated widely in Europe in the early Middle Ages, when most countries had no gold coins of their own.
bezel (n.)
1610s, "slope of the edge of a cutting tool," also "groove by which a stone is held in its setting," from Old French *besel (13c.; Modern French biseau), cognate with Spanish and Portuguese bisel; of uncertain origin, perhaps literally "a stone with two angles," from Vulgar Latin *bis-alus, from bis- "twice" (from PIE root *dwo- "two") + ala "wing, side" (see alar). Meaning "oblique face of a gem" is from c. 1840. The verb meaning "grind (a tool) down to an edge" is from 1670s. Compare bevel.
bezique (n.)
card game, 1861, from French bézigue (19c.), which is of unknown origin.Up to four can play, using two packs from which the number cards from 2 to 6 have been removed.
bezoar (n.)
1540s, "stone used as an antidote against poison," via Medieval Latin, from Arabic bazahr, from Persian pad-zahr "counter-poison," from pad "protecting, guardian, master" (from Iranian *patar-, source also of Avestan patar-, from PIE *pa-tor-, from root *pa- "to feed, protect") + zahr "poison" (from Old Iranian *jathra, from PIE *gwhn-tro-, from root *gwhen- "to strike, kill;" see bane). Later in reference to a concoction from solid matter found in the stomachs and intestines of ruminants, which was held to have antidotal qualities (1570s). Related: Bezoardic.
bezzle (v.)
variant of embezzle (q.v.).
Bhagavad-Gita (n.)
in Hindu scripture, a dialogue between Krishna and Arjuna inserted in Mahabharata; Sanskrit, from Bhaga, a god of wealth, from Sanskrit bhagah, literally "allotter, distributor, master, lord," from bhajati "assigns, allots, apportions, enjoys, loves" (related to Avestan baga, Old Persian baga "master, lord, god," from PIE root *bhag- "to share out, apportion; to get a share") + gita "song," fem. past participle of gayate "sings, calls," from PIE root *gei- "to sing" (source also of Avestan gatha "song," Lithuanian giedoti "to sing"). First translated into English 1785.
bhang (n.)
"dried leaves of Cannabis Indica," 1590s, from Hindi bhang "narcotic from hemp," from Sanskrit bhangah "hemp," which is perhaps cognate with Russian penika "hemp." The word first appears in Western Europe in Portuguese (1560s). It also was borrowed into Persian (bang) and Arabic (banj).
Himalayan land between Tibet and India, from Sanskrit bhota "Tibet" + anta "end." The local name is said to be Druk Yul "Land of the Dragon." Related: Bhutanese.
bi (adj.)
1956 as a colloquial abbreviation of bisexual.
word-forming element meaning "two, having two, twice, double, doubly, twofold, once every two," etc., from Latin bi- "twice, double," from Old Latin dvi- (cognate with Sanskrit dvi-, Greek di-, dis-, Old English twi-, German zwei- "twice, double"), from PIE root *dwo- "two."

Nativized from 16c. Occasionally bin- before vowels; this form originated in French, not Latin, and might be partly based on or influenced by Latin bini "twofold" (see binary). In chemical terms, it denotes two parts or equivalents of the substance referred to. Cognate with twi- and di- (1).
bi-weekly (adj.)
also biweekly, 1865, from bi- "two, twice" + weekly. The sense "twice a week" is the first attested, but that of "every two weeks" is equally implied and preferred, the other going with semi-weekly.
bialy (n.)
bagel with onion flakes sprinkled on it, by 1936, ultimately short for Białystok, city in modern Poland. The city is named for the Biała river (literally White River), that flows past it, from Polish biały "white" + stok "slope."
fem. proper name, from Italian, fem. of bianco "white," which is from Germanic (see blank (adj.)). A doublet of French Blanche, which also is from Germanic, and compare Gwen, which means the same thing.
biangular (adj.)
also bi-angular, "having two angles or corners," 1770; see bi- "two" + angular.
biannual (adj.)
also bi-annual; "occurring every six months, twice a year," 1837; see bi- + annual (adj.). Distinguished in sense from biennial, but the distinction is etymologically arbitrary. Related: Biannually; bi-annually.
biarticulate (adj.)
"having two joints," 1806; see bi- "two" + articulate.
bias (v.)
"giving a bias to, causing to incline to one side," 1610s literal; 1620s figurative; from bias (n.). Compare French biasier. Related: Biased; biasing.
bias (n.)
1520s, "oblique or diagonal line," from French biais "a slant, a slope, an oblique," also figuratively, "an expedient, means" (13c., originally in Old French a past participle adjective, "sideways, askance, against the grain"), a word of unknown origin. Probably it came to French from Old Provençal biais, which has cognates in Old Catalan and Sardinian, and is possibly via Vulgar Latin *(e)bigassius from Greek epikarsios "athwart, crosswise, at an angle," from epi- "upon" + karsios "oblique," from PIE *krs-yo-, suffixed form of root *sker- (1) "to cut."

In the old game of bowls, it was a technical term used in reference to balls made with a greater weight on one side (1560s), causing them to curve toward one side; hence the figurative use "a one-sided tendency of the mind" (1570s), and, at first especially in law, "undue propensity or prejudice."
The bias of education, the bias of class-relationships, the bias of nationality, the political bias, the theological bias--these, added to the constitutional sympathies and antipathies, have much more influence in determining beliefs on social questions than has the small amount of evidence collected. [Herbert Spencer, "The Study of Sociology," 1873]

For what a man had rather were true he more readily believes. Therefore he rejects difficult things from impatience of research; sober things, because they narrow hope; the deeper things of nature, from superstition; the light of experience, from arrogance and pride, lest his mind should seem to be occupied with things mean and transitory; things not commonly believed, out of deference to the opinion of the vulgar. Numberless in short are the ways, and sometimes imperceptible, in which the affections colour and infect the understanding. [Francis Bacon, "Novum Organum," 1620]
biased (adj.)
1610s in reference to bowling, 1660s in reference to persons; past participle adjective from bias (v.). The simple bias also formerly was used as an adjective.
biathlon (n.)
"athletic contest in which participants ski and shoot," 1956, from bi- "two" + Greek athlon, literally "contest," but in this case abstracted from pentathlon.
biaxial (adj.)
also bi-axial, "having two axes," 1833; see bi- + axial. Related: Biaxially; biaxiality.