Online Etymology Dictionary

briefs (n.): "short, tight underwear," 1934, from brief (adj.).
brier (n.1): "thorny shrub, heath," 1540s, variant of Middle English brere, from Old English brer (Anglian), brær (West Saxon) "brier, bramble, prickly bush," which is of unknown origin. Briar is the most recent variant (c. 1600). Originally used of prickly, thorny bushes in general, now mostly restricted to wild rose bushes. Used figuratively (in plural) for "troubles" from c. 1500.
brier (n.2): type of tobacco pipe introduced to England c. 1859 and made from the root of a certain shrub, 1868, from French bruyère "heath plant," from Old French bruiere "heather, briar, heathland, moor" (12c.), from Gallo-Roman *brucaria, from *brucus "heather," from Gaulish (compare Breton brug "heath," Old Irish froech). Form altered in English by influence of brier (n.1).
brig (n.): "two-masted square-rigged vessel," 1720, colloquial shortening of brigantine (q.v.). Apparently such vessels being used for prison ships upon retirement from active duty led to extended meaning "a jail," first recorded 1852.
brigade (n.): "subdivision of an army," 1630s, from French brigade "body of soldiers" (14c.), from Italian brigata "troop, crowd, gang," from brigare "brawl, fight," from briga "strife, quarrel," perhaps of Celtic (compare Gaelic brigh, Welsh bri "power") or Germanic origin.
brigadier (n.): 1670s, "officer in command of a brigade," from French brigadier, from brigade (see brigade).
brigand (n.): c. 1400, "lightly armed foot soldier," from Old French brigand (14c.), from Italian brigante "trooper, skirmisher, foot soldier," from brigare (see brigade). Sense of "one who lives by pillaging" is from early 15c., reflecting the lack of distinction between professional mercenary armies and armed, organized criminals.
brigantine (n.): "small two-masted ship," 1520s, from Middle French brigandin (15c.), from Italian brigantino, perhaps "skirmishing vessel, pirate ship," from brigante "skirmisher, pirate, brigand" from brigare "fight" (see brigade).
bright (adj.): Old English bryht, by metathesis from beorht "bright; splendid; clear-sounding; beautiful; divine," from Proto-Germanic *berhta- "bright" (source also of Old Saxon berht, Old Norse bjartr, Old High German beraht, Gothic bairhts "bright"), from PIE root *bhereg- "to gleam, white" (source also of Sanskrit bhrajate "shines, glitters," Lithuanian breksta "to dawn," Welsh berth "bright, beautiful"). Meaning "quick-witted" is from 1741.
Bright's disease: "chronic nephritis," 1831, so called for English physician Richard Bright (1789-1858), who in 1827 first described it.
brighten (v.): Old English *beorhtnian "to make bright" (see bright (adj.) + -en (1)). Intransitive sense, "to become brighter," attested from c. 1300. Figurative use from 1590s. Related: Brightened; brightening.
brightness (n.): Old English beorhtnes "brightness, clearness, splendor, beauty;" see bright + -ness.
brill (n.): kind of flat fish, late 15c., of unknown origin.
brilliance (n.): 1755, from brilliant + -ance. Figurative sense (of wit, intelligence, etc.) is from 1779. Distinguished from brilliancy in that the latter usually is applied to things measurable in degrees.
brilliancy (n.): 1747; see brilliant + -cy. Also compare brilliance.
brilliant (adj.): 1680s, from French brilliant "sparkling, shining" present participle of briller "to shine" (16c.), from Italian brillare "sparkle, whirl," perhaps from Vulgar Latin *berillare "to shine like a beryl," from berillus "beryl, precious stone," from Latin beryllus (see beryl). In reference to diamonds (1680s) it means a flat-topped cut invented 17c. by Venetian cutter Vincenzo Peruzzi.
brim (n.): c. 1200, brymme "edge of the sea," of obscure origin, perhaps akin to Old Norse barmr "rim, brim," probably related to German bräme "margin, border, fringe," from PIE *bhrem- "point, spike, edge." (Old English had brim in the sense "sea, surf," but this probably was from the Germanic stem *brem- "to roar, rage.") Extended by 1520s to cups, basins, hats.
brim (v.): "to fill to the brim," 1610s, from brim (n.). Intransitive sense ("be full to the brim") attested from 1818. Related: Brimmed; brimming.
brimful (adj.): 1520s, from brim (n.) + -ful.
brimming (adj.): "being full to the brim," 1660s, present participle adjective from brim (v.).
brimstone (n.): Old English brynstan, from brin- stem of brinnen "to burn" (see burn (v.)) + stan (see stone (n.)). In Middle English the first element also recorded as brem-, brom-, brum-, bren-, brin-, bron-, brun-, bern-, born-, burn-, burned-, and burnt-. Formerly "the mineral sulfur," now restricted to biblical usage.
The Lord reynede vpon Sodom and Gomor brenstoon and fier. [Wycliff's rendition (1382) of Gen. xix:24]
The Old Norse cognate compound brennusteinn meant "amber," as does German Bernstein.
brinded (adj.): early 15c., the older form of brindled (q.v.).
brindle (adj.): 1670s; see brindled.
brindled (adj.): "marked with streaks, streaked with a dark color," 1670s, from Middle English brended (early 15c.), from bren "brown color" (13c.), noun made from past participle of brennen "burn" (see burn (v.)); the derived adjective perhaps means "marked as though by branding or burning." Form altered perhaps by influence of kindled.
brine (n.): Old English bryne "brine," origin unknown; no known cognates beyond Dutch brijn, Flemish brijne.
bring (v.): Old English bringan "to bring, bring forth, produce, present, offer" (past tense brohte, past participle broht), from Proto-Germanic *brengan (source also of Old Frisian brenga, Middle Dutch brenghen, Old High German bringan, Gothic briggan); no exact cognates outside Germanic, but it appears to be from PIE root *bhrengk-, compound based on root *bher- (1) "to carry" (source also of Latin ferre; see infer).

The tendency to conjugate this as a strong verb on the model of sing, drink, etc., is ancient: Old English also had a rare strong past participle form, brungen, corresponding to modern colloquial brung. To bring down the house figuratively (1754) is to elicit applause so thunderous it collapses the roof.
brink (n.): early 13c., from Middle Low German brink "edge," or Danish brink "steepness, shore, bank, grassy edge," from Proto-Germanic *brenkon, probably from PIE *bhreng-, variant of root *bhren- "project, edge" (source also of Lithuanian brinkti "to swell").
brinkmanship (n.): also brinksmanship, with parasitic -s- and construction based on salesmanship, sportsmanship, etc.; from brink (the image of the brink of war dates to at least 1840).

Associated with the policies advocated by John Foster Dulles (1888-1959), U.S. Secretary of State 1953-1959. The word springs from Dulles' philosophy as outlined in a magazine interview [with Time-Life Washington bureau chief James Shepley] early 1956:
The ability to get to the verge without getting into the war is the necessary art. If you cannot master it, you inevitably get into war. If you try to run away from it, if you are scared to go to the brink, you are lost.
The quote was widely criticized by the Eisenhower Administration's opponents, and the first attested use of brinkmanship seems to have been in such a context, a few weeks after the magazine appeared, by Democratic presidential candidate Adlai Stevenson criticizing Dulles for "boasting of his brinkmanship, ... the art of bringing us to the edge of the nuclear abyss."
briny (adj.): c. 1600, from brine + -y (2). Used earlier of tears than of the ocean (1610s). Related: Brininess.
brio (n.): "liveliness, vivacity," 1734, from Italian brio, literally "mettle, fire, life," perhaps a shortened derivative of Latin ebrius "drunk." Or via Provençal briu "vigor," from Celtic *brig-o- "strength," from PIE root *gwere- (2) "heavy" (see grave (adj.)). Probably entered English via musical instruction con brio.
brioche (n.): enriched type of French bread, 1824, from French brioche (15c.), from brier "to knead the dough," Norman form of broyer "to grind, pound," from Proto-Germanic *brekan "to break" (see break (v.)).
briquette (n.): 1884, originally blocks of compressed coal dust held together by pitch, from French briquette (18c.), diminutive of brique (see brick (n.)).
bris (n.): Yiddish word for the circumcision ceremony, from bris milah, Ashkenazi pronunciation of brit milah "covenant of circumcision."
brisk (adj.): 1550s, as Scottish bruisk, probably an alteration of French brusque (see brusque). Related: Briskly; briskness.
brisket (n.): mid-14c., brusket, perhaps from Old French bruschet, with identical sense of the English word, or from Old Norse brjosk "gristle, cartilage" (related to brjost "breast") or Danish bryske or Middle High German brusche "lump, swelling;" from PIE *bhreus- "to swell, sprout" (see breast (n.)).
bristle (n.): Old English byrst "bristle," with metathesis of -r-, from Proto-Germanic *bursti- (source also of Middle Dutch borstel, German borste), from PIE *bhrsti- from root *bhars- "point, bristle" (source also of Sanskrit bhrstih "point, spike"). With -el, diminutive suffix.
bristle (v.): c. 1200 (implied in past participle adjective bristled) "set or covered with bristles," from bristle (n.). Meaning "become angry or excited" is 1540s, from the way animals show fight. Related: Bristling.
bristly (adj.): 1590s, from bristle (n.) + -y (2). Figurative sense is recorded from 1872. Related: Bristliness.
Bristol: City in western England, Middle English Bridgestow, from Old English Brycgstow, literally "assembly place by a bridge" (see bridge (n.) + stow). A local peculiarity of pronunciation adds -l to words ending in vowels. Of a type of pottery, 1776; of a type of glass, 1880. In British slang, "breast," 1961, from Bristol cities, rhyming slang for titties.
Brit (n.): U.S. colloquial shortening of Britisher or Briton, 1901, formerly (in common with Britisher) highly offensive to Englishmen traveling in the States, who regarded it as yet another instance of the "odious vulgarism" of the Americans, but Bret and Bryt were common Old English words for the (Celtic) Britons and survived until c. 1300. In Old French, Bret as an adjective meant "British, Breton; cunning, crafty; simple-minded, stupid."
Britain (n.): c. 1300, Breteyne, from Old French Bretaigne, from Latin Britannia, earlier Brittania, from Brittani "the Britons" (see Briton). The Old English place-name Brytenlond meant "Wales." If there was a Celtic name for the island, it has not been recorded.
Britannic (adj.): 1640s, from Latin Britannicus (see Britain).
britches (n.): 1905, from britch (1620s), an old variant of breeches.
brite: variant of bright (adj.). It figures in English phonetic spelling reform from at least the late 19c.; as an advertiser's word it dates from at least 1905 ("Star-brite Metal Polish," made by the Star-Brite Company of Lancaster, Pa., U.S.).
British (adj.): Old English Bryttisc "of or relating to (ancient) Britons," from Bryttas "natives of ancient Britain" (see Briton). First modern record of British Isles is from 1620s.
Briton (n.): Anglo-French Bretun, from Latin Brittonem (nominative Britto, misspelled Brito in MSS) "a member of the tribe of the Britons," from *Britt-os, the Celtic name of the Celtic inhabitants of Britain and southern Scotland before the 5c. Anglo-Saxon invasion drove them into Wales, Cornwall, and a few other corners. In 4c. B.C.E. Greek they are recorded as Prittanoi, which is said to mean "tattooed people." Exclusively in historical use after Old English period; revived when James I was proclaimed King of Great Britain in 1604, and made official at the union of England and Scotland in 1707.
Brittany (n.): French Bretagne, named for 5c. Romano-Celtic refugees from the Anglo-Saxon invasion of Britain who crossed the channel and settled there (see Britain). The Little Britain or Less Britain (lasse brutaine, c. 1300) of old, contrasted with the Great Britain. As a name for girls (with various spellings), almost unknown in U.S. before 1970, then a top-10 name for babies born between 1986 and 1995.
brittle (adj.): late 14c., britel, perhaps from an unrecorded Old English adjective *brytel, related to brytan "to crush, pound, to break to pieces," from Proto-Germanic stem *brutila- "brittle," from *breutan "to break up" (source also of Old Norse brjota "to break," Old High German brodi "fragile"), from PIE *bhreu- "to cut, break up" (see bruise (v.)). With -le, suffix forming adjectives with meaning "liable to."
bro (n.): colloquial abbreviation of brother, attested from 1660s.
broach (n.): "pointed instrument," c. 1300, from Old French broche (12c.) "spit for roasting, awl, point end, top," from Vulgar Latin *brocca "pointed tool," noun use of fem. of Latin adjective broccus "projecting, pointed" (used especially of teeth), perhaps of Gaulish origin (compare Gaelic brog "awl").