Bernicia Look up Bernicia at Dictionary.com
Anglo-Saxon kingdom in northernmost England, founded by mid-6c., eventually merged into Northumbria; the name evidently is a survival of a pre-invasion Celtic name, perhaps that represented by Welsh Bryneich.
Bernoulli's principle Look up Bernoulli's principle at Dictionary.com
named for Dutch mathematician Daniel Bernoulli (1700-1782), who published it in 1738.
berry (n.) Look up berry at Dictionary.com
Old English berie, from Proto-Germanic *basjom (source also of Old Norse ber, Middle Dutch bere, German Beere "berry;" Old Saxon winber, Gothic weinabasi "grape"), which is of unknown origin. This and apple are the only native fruit names.
berserk (adj.) Look up berserk at Dictionary.com
1844, from berserk (n.) "Norse warrior," by 1835, an alternative form of berserker (1822), a word which was introduced by Sir Walter Scott, from Old Norse berserkr (n.) "raging warrior of superhuman strength;" probably from *ber- "bear" + serkr "shirt," thus literally "a warrior clothed in bearskin." Thus not from Old Norse berr "bare, naked."
Thorkelin, in the essay on the Berserkir, appended to his edition of the Krisini Saga, tells that an old name of the Berserk frenzy was hamremmi, i.e., strength acquired from another strange body, because it was anciently believed that the persons who were liable to this frenzy were mysteriously endowed, during its accesses, with a strange body of unearthly strength. If, however, the Berserk was called on by his own name, he lost his mysterious form, and his ordinary strength alone remained. ["Notes and Queries," Dec. 28, 1850]
The adjectival use probably is from such phrases as berserk frenzy, or as a title (Arngrim the Berserk).
berserker (n.) Look up berserker at Dictionary.com
alternative form of berserk (q.v.), from Old Norse berserkr, accusative of berserk. This is the oldest form of the word in its revival in Modern English (1822), and perhaps Scott, who introduced it, mistook the -r for an agent-noun suffix. Further complicated because it has the form of the Old Norse plural, and English berserker sometimes is plural.
berth (n.) Look up berth at Dictionary.com
1620s, "convenient sea room" (both for ships and sailors), of uncertain origin, probably from bear (v.) + abstract noun suffix -th (2) as in strength, health, etc. Original sense is preserved in phrase to give (something or someone) wide berth. Meaning "place on a ship to stow chests, room for sailors" is from 1706; extended to non-nautical situations by 1778.
berth (v.) Look up berth at Dictionary.com
1660s, of ships, from berth (n.). Of persons (intransitive), from 1886. Related: Berthed; berthing.
Bertha Look up Bertha at Dictionary.com
fem. proper name, from Old High German Berahta, Perahta, the name of a goddess, literally "the bright one," from Old High German beraht, related to Old English beorht (see bright). Soldiers' nickname Big Bertha for large-bore German mortar of World War I is a reference to Frau Bertha Krupp von Bohlen und Halbach, owner of Krupp steel works 1903-43.
beryl (n.) Look up beryl at Dictionary.com
hard, lustrous mineral, c. 1300, from Old French beryl (12c., Modern French béryl), from Latin beryllus, from Greek beryllos, perhaps from Prakrit veruliya, from Sanskrit vaidurya-, of Dravidian origin, perhaps from the city of Velur (modern Belur) in southern India.

Medieval Latin berillus also was applied to any precious stone of a pale green color, to fine crystal, and to eyeglasses (the first spectacle lenses may have been made of beryl), hence German Brille "spectacles," from Middle High German berille "beryl," and French besicles (plural) "spectacles," altered 14c. from Old French bericle.
beryllium (n.) Look up beryllium at Dictionary.com
metallic element, 1863, so called because it figures in the composition of the pale green precious stone beryl and was identified in emerald (green beryl) in 1797 by French chemist Louis Nicolas Vauquelin (1763-1829) and first isolated in 1828. With metallic element ending -ium. At first and through 19c. also sometimes called glucinum or glucinium.
beseech (v.) Look up beseech at Dictionary.com
late 12c., bisecen "to beseech, beg urgently," from be- + Middle English secen "to seek" (see seek). German cognate besuchen is merely "to visit." Related: Besought; beseeching.
beseeching (n.) Look up beseeching at Dictionary.com
"supplication, prayer," c. 1300, verbal noun from beseech. Related: Beseechingly; beseechingness.
beseem (v.) Look up beseem at Dictionary.com
early 13c., from be- + seem (v.). Related: Beseemed; beseeming.
beseeming (adj.) Look up beseeming at Dictionary.com
1520s, present participle adjective from beseem.
beset (v.) Look up beset at Dictionary.com
Old English besettan "to put, place; own, keep; occupy, settle; cover, surround with, besiege," from Proto-Germanic *bisatjan (source also of Old Saxon bisettjan, Dutch bezetten, Old High German bisezzan, German besetzen, Gothic bisatjan); see be- + set (v.). The figurative sense also was in Old English. Related: Beset (past tense); besetting.
beshrew (v.) Look up beshrew at Dictionary.com
early 14c., "deprave, pervert, corrupt," from be- + shrew (v.) "to curse;" see shrew. Meaning "to invoke evil upon" is from late 14c.
beside (prep.) Look up beside at Dictionary.com
Old English be sidan "by the side of" (only as two words), from be- + sidan dative of side (n.). By 1200, formed as one word and used as both adverb and preposition. The alternative Middle English meaning "outside" led to the sense preserved in beside oneself "out of one's wits" (late 15c.).
besides (prep.) Look up besides at Dictionary.com
attested from c. 1200 (common after c. 1400), from beside + adverbial genitive -s. Once sharing all the senses of beside, now properly limited to "in addition to, otherwise."
besiege (v.) Look up besiege at Dictionary.com
c. 1300, from be- + siege. Related: Besieged; besieging.
besmear (v.) Look up besmear at Dictionary.com
Old English bismierwan, besmyrwan (West Saxon), besmerwan (Anglian); see be- + smear (v.). Related: Besmeared; besmearing.
besmirch (v.) Look up besmirch at Dictionary.com
1590s, from be- + smirch.
Our Gayness and our Gilt are all besmyrcht. ["Henry V," IV.iii.110]
Related: Besmirched; besmirching.
besom (n.) Look up besom at Dictionary.com
Old English besma "bundle of twigs" (used as a broom or a flail), from West Germanic *besmon (source also of Old Frisian besma, Old Saxon besmo, Old High German besmo, German Besen, Dutch bezem), which is of unknown origin. Perhaps "something bound or twisted," from PIE *bheidh-.
besot (v.) Look up besot at Dictionary.com
"affect with a foolish manifestation," 1570s, from be- + sot. Related: Besotted; besotting.
besotted (adj.) Look up besotted at Dictionary.com
past participle adjective from besot.
besought Look up besought at Dictionary.com
Middle English besohte, past tense and past participle of beseech.
bespangle (v.) Look up bespangle at Dictionary.com
1610s, from be- + spangle. Related: Bespangled; bespangling.
bespatter (v.) Look up bespatter at Dictionary.com
1640s, from be- + spatter (v.). Related: Bespattered; bespattering.
bespeak (v.) Look up bespeak at Dictionary.com
Old English besprecan "speak about, speak against, complain," from be- + sprecan "to speak" (see speak (v.)). A common Germanic compound (cognates: Old Saxon bisprecan, Dutch bespreken, Old High German bisprehhan, German besprechen); originally "to call out," it evolved a wide range of meaning in English, including "speak up," "oppose," "request," "discuss, "arrange," and "to order (goods)" (1580s).
The connection of the senses is very loose; some of them appear to have arisen quite independently of each other from different applications of BE- pref. [OED]
bespeckle (v.) Look up bespeckle at Dictionary.com
c. 1600, from be- + speckle. Related: Bespeckled; bespeckling.
bespectacled (adj.) Look up bespectacled at Dictionary.com
1742, past participle adjective from be- + spectacles.
bespoke (adj.) Look up bespoke at Dictionary.com
"custom or custom-made, made to order," of goods, as distinguished from ready-made, 1755, the same sense found earlier in bespoken (c. 1600), past participle of bespeak, in a sense of "to speak for, to arrange beforehand," a sense attested in bespeak from 1580s. Now usually of tailored suits.
bespread (v.) Look up bespread at Dictionary.com
c. 1200, from be- + spread (v.).
besprinkle (v.) Look up besprinkle at Dictionary.com
mid-15c., from be- + sprinkle (v.). Related: Besprinkled; besprinkling.
Bessemer Look up Bessemer at Dictionary.com
in reference to the process for decarbonizing and desiliconizing pig iron by passing air through the molten metal, 1856, named for engineer and inventor Sir Harry Bessemer (1813-1898) who invented it.
best (adj.) Look up best at Dictionary.com
Old English beste, reduced by assimilation of -t- from earlier Old English betst "best, first, in the best manner," originally superlative of bot "remedy, reparation," the root word now only surviving in to boot (see boot (n.2)), though its comparative, better, and superlative, best, have been transferred to good (and in some cases well). From Proto-Germanic root *bat-, with comparative *batizon and superlative *batistaz (source also of Old Frisian, Old Saxon, Middle Dutch best, Old High German bezzist, German best, Old Norse beztr, Gothic batists).
The best-laid schemes o' mice an' men
Gang aft agley,
An' lea'e us nought but grief an' pain,
For promis'd joy!

[Burns]
Best-seller as short for "best-selling book" is from 1902, apparently originally in the publishing trade; best friend was in Chaucer (late 14c.). Best girl is first attested 1881, American English; best man is 1814, originally Scottish, replacing groomsman. To be able to do something with the best of them is recorded by 1748.
best (v.) Look up best at Dictionary.com
"to get the better of," 1863, from best (adj.). Related: Bested; besting.
best (n.) Look up best at Dictionary.com
c. 1200, from best (adj.).
bestead (v.) Look up bestead at Dictionary.com
"to help, support, prop," 1580s, from be- + stead (v.); see stead.
bestest (adj.) Look up bestest at Dictionary.com
jocular emphatic superlative of best (which is itself a superlative), attested from 1834.
bestial (adj.) Look up bestial at Dictionary.com
late 14c., from Old French bestial (13c.) "relating to animals, stupid, foolish, bestial" and directly from Latin bestialis "like a beast," from bestia (see beast). Sense of "below the dignity of a human" is from c. 1400, and in many cases its use is unjust to the beasts.
bestiality (n.) Look up bestiality at Dictionary.com
late 14c., "the nature of beasts," from bestial + -ity. Meaning "indulgence in beastly instincts" is from 1650s; sense of "sexual activity with a beast" is from 1611 (KJV).
bestiary (n.) Look up bestiary at Dictionary.com
"medieval treatise on beasts" usually with moralistic overtones, 1818, from Medieval Latin bestiarium "a menagerie," also "a book about animals", from bestia (see beast). A Latin term for such works was liber de bestiis compositus. Roman bestiarius meant "a fighter against beasts in the public entertainments."
bestir (v.) Look up bestir at Dictionary.com
Old English bestyrian "to heap up," from be- + stir. Related: Bestirred; bestirring.
bestow (v.) Look up bestow at Dictionary.com
early 14c., bistowen "give" (as alms, etc.), from be- + stowen "to place" (see stow). Related: Bestowed; bestowing; bestower.
bestowal (n.) Look up bestowal at Dictionary.com
1773, from bestow + -al (2).
bestrew (v.) Look up bestrew at Dictionary.com
Old English bestreowian; see be- + strew (v.).
bestride (v.) Look up bestride at Dictionary.com
Old English bestridan "to bestride, mount," from be- + stridan "to stride" (see stride (v.)). Compare Middle Dutch bestryden.
bet Look up bet at Dictionary.com
1590s, as both a verb and noun, in the argot of petty criminals, of unknown origin; probably a shortening of abet or else from obsolete beet "to make good," from Old English bætan "make better, arouse, stimulate," from Proto-Germanic *baitjan, in which case the verb would be the original. The original notion is perhaps "to improve" a contest by wagering on it, or it is from the "bait" sense in abet. Used since 1852 in various American English slang assertions (compare you bet "be assured," 1857). Related: Betting.
beta (n.) Look up beta at Dictionary.com
second letter of the Greek alphabet, c. 1300, from Greek, from Hebrew/Phoenician beth (see alphabet); used to designate the second of many things. Beta radiation is from 1899 (Rutherford). Beta particle is attested from 1904.
betake (v.) Look up betake at Dictionary.com
c. 1200, from be- + take. Related: Betook; betaken.