Online Etymology Dictionary

broach (v.): "pierce," early 14c., from the same source as broach (n.). Meaning "begin to talk about" is 1570s, a figurative use with suggestions of "broaching" a cask or of spurring into action (compare Old French brochier, 12c., "to spur," also "to penetrate sexually"). Related: Broached broaching.
broad (adj.): Old English brad "broad, flat, open, extended," from Proto-Germanic *braithaz (source also of Old Frisian bred, Old Norse breiðr, Dutch breed, German breit, Gothic brouþs), which is of unknown origin. Not found outside Germanic languages. No clear distinction in sense from wide. Related: Broadly. Broad-brim as a style of hat (1680s, broad-brimmed) in 18c.-19c. suggested "Quaker male" from their characteristic attire.
broad (n.): "woman," slang, 1911, perhaps suggestive of broad (adj.) hips, but it also might trace to American English abroadwife, word for a woman (often a slave) away from her husband. Earliest use of the slang word suggests immorality or coarse, low-class women. Because of this negative association, and the rise of women's athletics, the track and field broad jump was changed to the long jump c. 1967.
broad-minded (adj.): 1590s; see broad (adj.) + minded. This abstract mental sense of broad existed in Old English; for example in bradnes "breadth," also "liberality."
broadband (n.): type of high-speed Internet access widely available from 2006, from broad (adj.) + band (n.1).
broadcast: 1767, adjective, in reference to the spreading of seed, from broad (adj.) + past participle of cast (v.). Figurative use is recorded from 1785. Modern media use began with radio (1922, adjective and noun). As a verb, recorded from 1813 in an agricultural sense, 1829 in a figurative sense, 1921 in reference to radio.
broadcasting (n.): 1922, verbal noun from broadcast (v.).
broaden (v.): 1727, from broad (adj.) + -en (1). The word seems no older than this date (discovered by Johnson in one of James Thomson's "Seasons" poems); broadened also is first found in the same poet, and past participle adjective broadening is recorded from 1850.
broadside (n.): 1590s, "side of a ship" (technically, "the side of a ship above the water, between the bow and the quarter"), from broad (adj.) + side (n.); thus "the artillery on one side of a ship all fired off at once" (1590s, with figurative extensions). Two words until late 18c. Of things other than ships, 1630s. But oldest-recorded sense in English is "sheet of paper printed only on one side" (1570s).
broadsword (n.): Old English brad swurd, from broad (adj.) + sword.
Broadway: common street name, from broad (adj.) + way (n.); the allusive use for "New York theater district" is first recorded 1881.
Brobdingnag: (not *brobdignag), 1727, Swift's name in "Gulliver's Travels" for imaginary country where everything was on a gigantic scale.
brobdingnagian (adj.): "huge, immense, gigantic," 1728, from Brobdingnag + -ian.
brocade (n.): 1560s, from Spanish brocado, from Italian broccato "embossed cloth," originally past participle of broccare "to stud, set with nails," from brocco "small nail," from Latin broccus "projecting, pointed" (see broach (n.)).
brocade (v.): 1650s (implied in brocaded), from brocade (n.). Related: Brocading.
broccoli (n.): 1690s, from Italian broccoli, plural of broccolo "a sprout, cabbage sprout," diminutive of brocco "shoot, protruding tooth, small nail" (see brocade (n.)).
broch (n.): prehistoric stone tower of the Scottish Highland and isles, 1650s, from Scottish broch, from Old Norse borg "castle," cognate with Old English burh (see borough).
brochure (n.): 1748, "pamphlet; short written work stitched together," from French brochure "a stitched work," from brocher "to stitch" (sheets together), from Old French brochier "to prick, jab, pierce," from broche "pointed tool, awl" (see broach (n.)).
brock (n.): Old English brocc "badger," a borrowing from Celtic (compare Old Irish brocc, Welsh broch). After c. 1400, often with the adjective stinking, and meaning "a low, dirty fellow."
brogans (n.): type of coarse shoes, 1846, from Irish and Gaelic brogan, diminutive of brog "shoe" (also see brogue).
brogue (n.): type of Celtic accent, 1705, perhaps from the meaning "rough, stout shoe" worn by rural Irish and Scottish highlanders (1580s), via Gaelic or Irish, from Old Irish broce "shoe," thus originally meaning something like "speech of those who call a shoe a brogue." Or perhaps it is from Old Irish barrog "a hold" (on the tongue).
broil (v.1): "to cook," late 14c. (earlier "to burn," mid-14c.), from Old French bruller "to broil, roast" (Modern French brûler), earlier brusler "to burn" (11c.), which, with Italian bruciare, is of uncertain and much-disputed origin.

Perhaps from Vulgar Latin *brodum "broth," borrowed from Germanic and ultimately related to brew (v.). Gamillscheg proposes it to be from Latin ustulare "to scorch, singe" (from ustus, past participle of urere "to burn") and altered by influence of Germanic "burn" words beginning in br-. Related: Broiled; broiling.
broil (v.2): early 15c., "to quarrel, brawl," also "mix up, present in disorder," from Anglo-French broiller "mix up, confuse," Old French brooillier "to mix, mingle," figuratively "to have sexual intercourse" (13c., Modern French brouiller), perhaps from breu, bro "stock, broth, brew," from Frankish or another Germanic source (compare Old High German brod "broth") akin to broth (see brew (v.)); also compare imbroglio.
broiler (n.): late 14c., "grill or gridiron used in broiling," agent noun from broil (v.1). From c. 1300 as a surname, perhaps meaning "cook who specializes in broiling." Meaning "chicken for broiling" is from 1876.
broke (adj.): past tense and obsolete past participle of break (v.); extension to "insolvent" is first recorded 1716 (broken in this sense is attested from 1590s). Old English cognate broc meant, in addition to "that which breaks," "affliction, misery."
broken (adj.): late 14c., past participle adjective from break (v.). Broken record in reference to someone continually repeating the same thing is from 1944, in reference to scratches on records that cause the needle to jump back and repeat.
When Britain's Minister of State, Selwyn Lloyd[,] became bored with a speech by Russia's Andrei Vishinsky in UN debate, he borrowed a Dizzy Gillespie bebop expression and commented: "Dig that broken record." While most translators pondered the meaning, a man who takes English and puts it into Chinese gave this translation: "Recover the phonograph record which you have discarded." ["Jet," Oct. 15, 1953]
broken-hearted (adj.): also brokenhearted, 1520s, from broken + hearted. Related: Broken-heartedly; broken-heartedness.
broker (n.): mid-14c. (mid-13c. in surnames), "commercial agent, factor," also "an agent in sordid business," from Anglo-French brocour "small trader," from abrokur "retailer of wine, tapster;" perhaps from Portuguese alborcar "barter," but more likely from Old French brocheor, from brochier "to broach, tap, pierce (a keg)," from broche "pointed tool" (see broach (n.)), giving original sense of "wine dealer," hence "retailer, middleman, agent." In Middle English, used contemptuously of peddlers and pimps, "one who buys and sells public office" (late 14c. in Anglo-French), "intermediary in love or marriage" (late 14c.).
broker (v.): 1630s (implied in brokering), from broker (n.). Related: Brokered.
brokerage (n.): mid-15c., "a broker's trade," from broker (n.) + -age. Also, in 17c., "a pimp's trade."
brolly (n.): British slang, "umbrella," by 1866, a clipped and shortened form of umbrella.
bromeliad (n.): from Modern Latin Bromeliaceæ, family name given by Linnæus, for Olaus Bromel (1639-1705), Swedish botanist. Related: Bromeliads.
bromide (n.): compound of bromine and another metal or radical, 1836, from bromine, the pungent, poisonous element, + -ide. Used as a sedative; figurative sense of "dull, conventional person or trite saying" popularized by U.S. humorist Frank Gelett Burgess (1866-1951) in his book "Are You a Bromide?" (1906). Related: Bromidic.
bromine (n.): nonmetallic element, 1827, from French brome, from Greek bromos "stench." With chemical suffix -ine (2). The evil-smelling dark red liquid was discovered by French chemist Antoine Jérôme Balard (1802-1876), who initially called it muride.
bronchial (adj.): c. 1735, from Late Latin bronchus, from Greek bronkhos "windpipe, throat" (from PIE *gwro-nkh-, from root *gwere- (4) "to swallow;" see voracity) + -al (1). bronchial tubes is from 1847.
bronchiectasis (n.): Modern Latin, from Greek bronkhia "the bronchial tubes" (plural; see bronchial) + ektasis "a stretching out, extension, dilation."
bronchiole (n.): Modern Latin, from diminutive of bronchia "the bronchial tubes" (plural; see bronchial).
bronchitis (n.): coined in Modern Latin 1808 by Charles Bedham, from bronchia "the bronchial tubes" (plural; see bronchial) + -itis "inflammation."
bronchoscopy (n.): from German bronchoskopie (1898), from Latinized comb. form of Greek bronkhia "the bronchial tubes" (plural; see bronchial); also see -scope.
bronchus (n.): 1706 (plural bronchi), from Greek bronkhos "the wind pipe" (see bronchial).
bronco (n.): also broncho, 1850, American English, "untamed or half-tamed horse," from noun use of Spanish bronco (adj.) "rough, rude," originally a noun meaning "a knot in wood," perhaps from Vulgar Latin *bruncus "a knot, projection," apparently from a cross of Latin broccus "projecting" (see broach (n.)) + truncus "trunk of a tree" (see trunk (n.1)). Bronco-buster is attested from 1886.
brontosaurus (n.): 1879, Modern Latin, from Greek bronte "thunder" (perhaps from PIE imitative root *bhrem- "to growl") + -saurus. Brontes was the name of one of the Cyclopes in Greek mythology.
Bronx: named for Jonas Bronck, who settled there in 1641.
Jonas Bronck, who arrived at New Amsterdam in 1639, and whose name is perpetuated in Bronx Borough, Bronx Park, Bronxville -- in New York -- was a Scandinavian, in all probability a Dane and originally, as it seems, from Thorshavn, Faroe Islands, where his father was a pastor in the Lutheran Church. Faroe then belonged to Denmark-Norway and had been settled by Norwegians. The official language of the island in Bronck's days was Danish. ... Bronck may have been a Swede if we judge by the name alone for the name of Brunke is well known in Sweden. [John Oluf Evjen, "Scandinavian immigrants in New York, 1630-1674," Minneapolis, 1916]
Bronx cheer first recorded 1929.
bronze (n.): 1721, "alloy of copper and tin," from French bronze, from Italian bronzo, from Medieval Latin bronzium. Perhaps cognate (via notion of color) with Venetian bronza "glowing coals," or German brunst "fire." Perhaps influenced by Latin Brundisium the Italian town of Brindisi (Pliny writes of aes Brundusinum). Perhaps ultimately from Persian birinj "copper."

In Middle English, the distinction between bronze (copper-tin alloy) and brass (copper-zinc alloy) was not clear, and both were called bras. A bronze medal was given to a third-place finisher since at least 1852. The archaeological Bronze Age (1865) falls between the Stone and Iron ages, and is a reference to the principal material for making weapons and ornaments.
bronze (v.): 1640s, literally, 1726 figuratively, from French bronzer (16c.) or else from bronze (n.). Related: Bronzed; bronzing. Meaning "to make to be bronze in color" is from 1792.
brooch (n.): early 13c., from Old French broche "long needle" (see broach (n.)). Specialized meaning led 14c. to distinct spelling.
brood (n.): Old English brod "brood, fetus, hatchling," from Proto-Germanic *brod (source also of Middle Dutch broet, Old High German bruot, German Brut "brood"), literally "that which is hatched by heat," from *bro- "to warm, heat," from PIE *bhre- "burn, heat, incubate," from root *bhreue- "to boil, bubble, effervesce, burn" (see brew (v.)).
brood (v.): "sit on eggs, hatch," mid-15c., from brood (n.). The figurative meaning ("to incubate in the mind") is first recorded 1570s, from notion of "nursing" one's anger, resentment, etc. Related: Brooded; brooding.
brooding (adj.): 1640s, "hovering, overhanging" (as a mother bird does her nest), from present participle of brood (v.); meaning "that dwells moodily" first attested 1818 (in "Frankenstein").
brooding (n.): "action of incubating," c. 1400, verbal noun from brood (v.). Figuratively (of weather, etc.) from 1805; of mental fixations by 1873. Related: Broodingly.