Online Etymology Dictionary

bereft (adj.): late 14c., past participle adjective from bereave (v.).
Berenice: fem. proper name, from Latin Berenice, from Macedonian Greek Berenike (classical Greek Pherenike), literally "bringer of victory," from pherein "to bring" (see infer) + nike "victory." The constellation Berenice's hair is from the story of the pilfered locks of the wife of Ptolemy Euergetes, king of Egypt, c. 248 B.C.E., which the queen cut off as an offering to Venus. The constellation features a dim but visible star cluster. But the earliest use of the phrase in astronomy in English was as a name for the star Canopus (1601).
beret (n.): also berret, 1827, from French béret, 19c., from dialect of Béarn, from Old Gascon berret "cap," from Medieval Latin birretum, diminutive of Late Latin birrus "a large hooded cloak," perhaps of Gaulish origin. The round, flat cap originally was worn by Basque peasants.
Beretta (n.): Italian firearms manufacturer, business attested from 1520s, founded by gunsmith Bartolomeo Beretta (1498-1565) of Lombardy.
berg (n.): short for iceberg, attested from 1823.
bergamot (n.): type of citrus tree, also its fruit, both similar to bitter orange, and the essence prepared from the oil of the rind of the fruit, 1690s, from French bergamote (17c.), from Italian bergamotta, named for Bergamo, town in Italy. The name is Roman Bergamum, from a Celtic or Ligurian berg "mountain," cognate with the identical Germanic word.

Earlier (1610s) as a kind of pear deemed especially luscious, in this sense ultimately a Romanic folk-etymologization from Turkish beg-armudi "prince's pear" or "prince of pears," influenced in form by the other word, but probably not from it (the town is on the opposite end of the peninsula from where the pear grows). Also used of garden plants of the mint order with a smell like that of oil of bergamot.
beriberi (n.): also beri-beri, paralytic disease prevalent in much of India, 1703, literally "great weakness," intensifying reduplication of Sinhalese beri "weakness."
Bering: strait and sea between Alaska and Siberia, named for Danish explorer Vitus Bering (1681-1741), who worked for Peter the Great and led the first European expedition to sight Alaska, in 1741.
berk (n.): "fool," 1936, abbreviation of Berkshire Hunt (or Berkeley Hunt), rhyming slang for cunt but typically applied only to contemptible persons, not to the body part.
This is not an objective, anatomical term, neither does it imply coitus. It connects with that extension of meaning of the unprintable, a fool, or a person whom one does not like. ["Dictionary of Rhyming Slang," 1960]
Berkshire: Old English Bearrocscir (893), from an ancient Celtic name meaning "hilly place" + Old English scir "shire, district."
Berlin: city in Brandenburg, capital of Germany, traditionally by folk-etymology from German Bär "bear," but likely from a Slavic source, compare Old Polabian berl-, birl- "swamp," in reference to the old city's location on low, marshy ground along the River Spree. A flashpoint city in the Cold War, the Berlin airlift ran from June 28, 1948 to May 12, 1949. The Berlin Wall began to be built Aug. 15, 1961, and was effective until Nov. 9, 1989.
berlin (n.): old type of four-wheeled covered carriage, 1690s, so called because it was introduced in Brandenburg, c. 1670; see Berlin. Hence berline (from the French form) "automobile with a glass partition behind the driver's seat." In reference to a type of wool and the popular patterns made for it, from 1841.
berm (n.): "narrow ledge," 1729, from French berme (17c.), from Old Dutch baerm "edge of a dike," probably related to brim (q.v.). In U.S., 19c., also the name for the bank of a canal opposite the tow path.
Bermuda: Atlantic island, named for Spanish explorer Juan de Bermudez (d.1570), who discovered it c. 1515. Bermuda shorts first attested 1946 (in "The Princeton Alumni Weekly"), from the type of garb worn by U.S. tourists there. Bermuda triangle in the supernatural sense was popular from 1972. As the adjective form, Bermudian (1777) holds seniority over Bermudan (1895).
Bern: Swiss capital, probably originally from PIE root *ber- "marshy place," but by folk etymology from German Bär "bear" (compare Berlin). Related: Bernese.
Bernard: masc. proper name, from German Bernhard, literally "bold as a bear," from Old High German bero "bear" (see bear (n.)) + harti "hard, bold, strong" (see hard (adj.)).
Bernicia: 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: named for Dutch mathematician Daniel Bernoulli (1700-1782), who published it in 1738.
berry (n.): 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.): 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.): 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.): 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.): 1660s, of ships, from berth (n.). Of persons (intransitive), from 1886. Related: Berthed; berthing.
Bertha: 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.): 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.): 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.): 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.): "supplication, prayer," c. 1300, verbal noun from beseech. Related: Beseechingly; beseechingness.
beseem (v.): early 13c., from be- + seem (v.). Related: Beseemed; beseeming.
beseeming (adj.): 1520s, present participle adjective from beseem.
beset (v.): 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.): early 14c., "deprave, pervert, corrupt," from be- + shrew (v.) "to curse;" see shrew. Meaning "to invoke evil upon" is from late 14c.
beside (prep.): 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.): 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.): c. 1300, from be- + siege. Related: Besieged; besieging.
besmear (v.): Old English bismierwan, besmyrwan (West Saxon), besmerwan (Anglian); see be- + smear (v.). Related: Besmeared; besmearing.
besmirch (v.): 1590s, from be- + smirch.
Our Gayness and our Gilt are all besmyrcht. ["Henry V," IV.iii.110]
Related: Besmirched; besmirching.
besom (n.): 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.): "affect with a foolish manifestation," 1570s, from be- + sot. Related: Besotted; besotting.
besotted (adj.): past participle adjective from besot.
besought: Middle English besohte, past tense and past participle of beseech.
bespangle (v.): 1610s, from be- + spangle. Related: Bespangled; bespangling.
bespatter (v.): 1640s, from be- + spatter (v.). Related: Bespattered; bespattering.
bespeak (v.): 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.): c. 1600, from be- + speckle. Related: Bespeckled; bespeckling.
bespectacled (adj.): 1742, past participle adjective from be- + spectacles.
bespoke (adj.): "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.): c. 1200, from be- + spread (v.).
besprinkle (v.): mid-15c., from be- + sprinkle (v.). Related: Besprinkled; besprinkling.
Bessemer: 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.