blue (v.) Look up blue at Dictionary.com
"to make blue," c. 1600, from blue (adj.1).
blue (n.) Look up blue at Dictionary.com
"the color of the clear sky," c. 1300, from blue (adj.1). From late 15c. as "blue clothing." The blue is from 1640s as "the sky" (hence bolt from the blue "lightning," 1837); from 1821 as "the sea." In reference to a particular party which has chosen blue for its color, by 1835. "In most parts of England the Conservative party" [OED], but in 17c. it often was the Whig color (opposed to royal red).
blue laws Look up blue laws at Dictionary.com
1781, severe Puritanical code said to have been enacted formerly in New Haven and Connecticut colonies; of uncertain origin, perhaps from the notion of coldness, or from one of the figurative senses in blue (adj.1). Blue was the color adopted by 17c. Scottish Covenanters (in contradistinction to the royal red) and hence the color for a time acquired an association with strictness in morals or religion. Or perhaps connected to bluestocking in the sense of "puritanically plain or mean" (see bluestocking, which is a different application of the same term); the parliament of 1653 was derisively called the bluestocking parliament. The common explanation that they were written on blue paper is not considered valid; pale blue paper was used for many old U.S. legal documents and there would have been nothing notable about its use in this case.
The assertion by some writers of the existence of the blue laws has no other basis than the adoption by the first authorities of the New Haven colony of the Scriptures as their code of law and government, and their strict application of Mosaic principles. [Century Dictionary]
blue moon (n.) Look up blue moon at Dictionary.com
1821 in phrases indicating something rarely occurring, often suggesting something that, in fact, never happens. Compare at the Greek calends, and the native in the reign of Queen Dick and Saint Geoffrey's Day "Never, there being no saint of that name," reported in Grose (1788). It is suggested earliest in this couplet from 1528:
Yf they say the mone is blewe,
We must beleve that it is true.
Though this might refer to calendrical calculations by the Church. Thus the general "rareness" sense of the term is difficult to disentangle from the specific calendrical one (commonly misinterpreted as "second full moon in a calendar month," but actually a quarterly calculation). In either case, the sense of blue here is obscure. Literal blue moons do sometimes occur under extreme atmospheric conditions.
blue-blood (adj.) Look up blue-blood at Dictionary.com
1809 in reference to the blood that flows in the veins of the old and aristocratic families of Spain, translating Spanish sangre azul, claimed by certain families of Castile that held themselves uncontaminated by Moorish or Jewish admixture; the term probably is from the notion of the visible veins of people of fair complexion. In reference to English families by 1827. As a noun, "member of an old and aristocratic family," by 1877. See blue (adj.1) + blood (n.).
blue-chip (adj.) Look up blue-chip at Dictionary.com
1904 in reference to the high-value poker counter, also in the figurative sense of "valuable;" stock exchange sense, in reference to "shares considered a reliable investment," is first recorded 1929; especially of stocks that saw spectacular rises in value in the four years or so before the Wall Street crash of that year wiped out most of it. See blue (adj.1) + chip (n.1).
blue-collar (adj.) Look up blue-collar at Dictionary.com
1949, from blue (adj.1) + collar (n.). From the common color of men's work shirts.
blue-jeans (n.) Look up blue-jeans at Dictionary.com
from 1843 as a type of fabric; see blue (adj.1) + jean. As short for blue-jeans trousers, from 1878.
bluebell (n.) Look up bluebell at Dictionary.com
also blue-bell, popular name of various plants with flowers blue and more or less bell-shaped, 1570s, from blue (adj.1) + bell (n.).
blueberry (n.) Look up blueberry at Dictionary.com
c. 1775, from blue (1) + berry.
bluebird (n.) Look up bluebird at Dictionary.com
also blue-bird, North American warbler-like bird, 1680s, from blue (1) in reference to its plumage + bird (n.1). Figurative use in bluebird of happiness is from 1909 play romance "l'Oiseau bleu," literally "The Blue Bird," by Belgian dramatist and poet Maurice Maeterlinck (1862-1949).
bluegrass (n.) Look up bluegrass at Dictionary.com
also blue-grass, music style, 1958, in reference to the Blue Grass Boys, country music band 1940s-'50s, from the "blue" grass (Poa pratensis) characteristic of Kentucky, the grass so called from 1751. Kentucky has been called the Bluegrass State at least since 1872; see blue (1) + grass.
blueing (n.) Look up blueing at Dictionary.com
"substance which makes (something) blue," 1660s, verbal noun from blue (v.).
blueprint (n.) Look up blueprint at Dictionary.com
also blue-print, 1882, from blue (1) + print (n.). The process uses blue on white, or white on blue. Figurative sense of "detailed plan" is attested from 1926. As a verb by 1939.
blues (n.) Look up blues at Dictionary.com
"music form featuring flatted thirds and sevenths," possibly c. 1895 (though officially 1912, in W.C. Handy's "Memphis Blues"). Blue note "minor interval where a major would be expected" is from 1919.

The meaning "depression, low spirits" goes back to 1741, from blue (adj.1) "low-spirited" (c. 1400).
bluestocking (n.) Look up bluestocking at Dictionary.com
also blue-stocking, 1790, derisive word for a woman considered too learned, traces to a London literary salon founded c. 1750 by Elizabeth Montagu on the Parisian model, featuring intellectual discussion instead of card games, and in place of ostentatious evening attire, simple dress, including Benjamin Stillingfleet's blue-gray tradesman's hose which he wore in place of gentleman's black silk, hence the term, first applied in derision to the whole set by Admiral Boscawen. None of the ladies wore blue stockings. Borrowed by the neighbors in loan-translations, such as French bas-bleu, Dutch blauwkous, German Blaustrumpf.
bluesy (adj.) Look up bluesy at Dictionary.com
1946, from blues + -y (2).
bluff (n.2) Look up bluff at Dictionary.com
1844 as an alternative name for poker; from bluff (v.). As "an act of bluffing" by 1864. Blind man's bluff formerly was called hoodman-blind (1560s).
bluff (v.) Look up bluff at Dictionary.com
1839, American English, poker term, perhaps from Dutch bluffen "to brag, boast," or verbluffen "to baffle, mislead." An identical word meant "blindfold, hoodwink" in 1670s, but the sense evolution and connection are unclear; OED calls it "one of the numerous cant terms ... which arose between the Restoration and the reign of Queen Anne." Extended or figurative sense by 1854. Related: Bluffed; bluffing.
bluff (n.1) Look up bluff at Dictionary.com
"broad, vertical cliff," 1680s, from bluff (adj.) "with a broad, flat front" (1620s), a sailors' word, probably from Dutch blaf "flat, broad." Apparently a North Sea nautical term for ships with flat vertical bows, later extended to landscape features.
bluffing (n.) Look up bluffing at Dictionary.com
1845, in the poker sense, verbal noun from bluff (v.).
bluffs (n.) Look up bluffs at Dictionary.com
see bluff (n.1).
bluish (adj.) Look up bluish at Dictionary.com
late 14c., blewysh; see blue (1) + -ish.
blunder (n.) Look up blunder at Dictionary.com
mid-14c., apparently from blunder (v.), though of about the same age.
blunder (v.) Look up blunder at Dictionary.com
mid-14c., "to stumble about blindly," from a Scandinavian source akin to Old Norse blundra "shut one's eyes," from PIE root *bhlendh- (see blind). Meaning "make a stupid mistake" is first recorded 1711. Related: Blundered; blundering.
blunderbuss (n.) Look up blunderbuss at Dictionary.com
1650s, from Dutch donderbus, from donder "thunder" (Middle Dutch doner, donder, from Proto-Germanic *thunaraz; see thunder (n.)) + bus "gun" (originally "box, tube"); altered by resemblance to blunder.
blunderful (adj.) Look up blunderful at Dictionary.com
1881, jocular blend of blunder and wonderful.
blundering Look up blundering at Dictionary.com
mid-14c. as a present participle adjective; mid-15c. as a verbal noun, from blunder (v.). Related: Blunderingly.
blunt (v.) Look up blunt at Dictionary.com
late 14c., from blunt (adj.). Related: Blunted; blunting.
blunt (n.) Look up blunt at Dictionary.com
street slang for "marijuana and tobacco cigar" (easier to pass around, easier to disguise, and the stimulant in the tobacco enhances the high from the pot) surfaced c. 1993, but is said to have originated among Jamaicans in New York City in the early 1980s; from Phillies Blunt brand cigars; see blunt (adj.), which has been used of certain cigars since 19c.
Users say that the Phillies Blunt brand produces less harsh-tasting or sweeter smoke. The leaf wrapper of a Phillies Blunt is strong enough to hold together through the manipulations of making a blunt. Other brands fall apart. [http://nepenthes.lycaeum.org/Drugs/THC/Smoke/blunts.html]
blunt (adj.) Look up blunt at Dictionary.com
c. 1200, "dull, obtuse," perhaps from or related to Old Norse blundra (see blunder (v.)). Of tools or weapons, late 14c. Meaning "abrupt of speech or manner" is from 1580s.
bluntly (adv.) Look up bluntly at Dictionary.com
1550s, "stupidly," from blunt (adj.) + -ly (2). Meaning "directly" is from 1570s.
bluntness (n.) Look up bluntness at Dictionary.com
late 15c., "stupidity," from blunt (adj.) + -ness. Meaning "rudeness" is from c. 1600.
blur (v.) Look up blur at Dictionary.com
1580s, and thus probably from blur (n.), but the dates are close and either might be the original. Related: Blurred; blurring.
blur (n.) Look up blur at Dictionary.com
1540s, "smear on the surface of writing;" perhaps akin to blear. Extended sense of "confused dimness" is from 1860.
blurb (n.) Look up blurb at Dictionary.com
used by U.S. scholar Brander Matthews (1852-1929) in 1906 in "American Character;" popularized 1907 by U.S. humorist Frank Gelett Burgess (1866-1951). Originally mocking excessive praise printed on book jackets.
Gelett Burgess ... then entertained the guests with some characteristic flashes of Burgessian humor. Referring to the word "blurb" on the wrapper of his book he said: "To 'blurb' is to make a sound like a publisher. The blurb was invented by Frank A. Munsey when he wrote on the front of his magazine in red ink 'I consider this number of Munsey's the hottest pie that ever came out of my bakery.' ... A blurb is a check drawn on Fame, and it is seldom honored.["] ["Publishers' Weekly," May 18, 1907]
blurry (adj.) Look up blurry at Dictionary.com
1855, from blur + -y (2). Related: Blurrily; blurriness.
blurt (v.) Look up blurt at Dictionary.com
1570s, probably echoic. Related: blurted; blurting. As a noun, 1570s, probably from the verb.
blush (n.) Look up blush at Dictionary.com
mid-14c., "a look, a glance" (sense preserved in at first blush), also "a gleam, a gleaming" (late 14c.), from blush (v.). As "a reddening of the face" from 1590s. Meaning "a rosy color" is 1590s.
blush (v.) Look up blush at Dictionary.com
mid-14c., bluschen, blischen, probably from Old English blyscan "blush, become red, glow" (glossing Latin rutilare), akin to blyse "torch," from Proto-Germanic *blisk- "to shine, burn," which also yielded words in Low German (Dutch blozen "to blush") and Scandinavian (Danish blusse "to blaze; to blush"); ultimately from PIE *bhel- (1) "to shine, flash, burn."

For vowel evolution, see bury. Earliest recorded senses were "to shine brightly; to look, stare." Sense of "turn red in the face" (with shame, modesty, etc.) is from c. 1400. Related: Blushed; blushing.
bluster (n.) Look up bluster at Dictionary.com
1580s, from bluster (v.).
bluster (v.) Look up bluster at Dictionary.com
late 14c., from a Low German source, such as Middle Low German blüstren "to blow violently," East Frisian blüstern "to bluster" (see blow (v.1)). Related: Blustered; blustering.
blustery (adj.) Look up blustery at Dictionary.com
1707, from bluster (n.) + -y (2). Blustering in this sense is recorded from 1510s.
BMX Look up BMX at Dictionary.com
1978, semi-acronym from bicycle motocross.
bo tree (n.) Look up bo tree at Dictionary.com
1680s, from Sinhalese bo, from Pali bodhi, short for bodhi-taru "bo tree," literally "tree of wisdom or enlightenment" (related to Sanskrit buddhah "awakened," from PIE root *bheudh- "be aware, make aware") + taru "tree."
boa (n.) Look up boa at Dictionary.com
late 14c., "large snake," from Latin boa, type of large serpent mentioned in Pliny's "Natural History;" origin unknown (in Middle English folk etymology associated with Greek bous "ox"). Extension to "snake-like coil of fur worn by ladies" is from 1836. The popular name boa constrictor is from 1788.
Boanerges Look up Boanerges at Dictionary.com
name given by Christ to his disciples John and James, the two sons of Zebedee (Mark iii.17), Late Latin, from Ecclesiastical Greek Boanerges, from a Galilean dialectal corruption of Hebrew bene reghesh "sons of rage" (interpreted in Greek as "sons of thunder"), from bene (see B'nai B'rith) + reghesh "commotion, tumult, throng." Applied figuratively to zealous or loud preachers.
boar (n.) Look up boar at Dictionary.com
Old English bar "boar," from Proto-Germanic *bairaz (source also of Old Saxon ber, Dutch beer, Old High German ber "a boar"), which is of unknown origin with no cognates outside West Germanic. Applied in Middle English to persons of boar-like character.
board (v.) Look up board at Dictionary.com
verb senses derived from various senses of board (n.1) and board (n.2) include "come alongside" (a ship), mid-15c. (from n.2); "put boards on, frame with boards," late 14c. (implied in boarded, from n.1); " to get onto" (a ship), 1590s, transferred from mid-19c. to stages, railway cars, aircraft, etc. (from n.2). Meaning "to be supplied with food and lodging" is from 1550s (from n.1 in transferred sense). Transitive meaning "provide with daily meals and lodging" is from 1590s. Related: Boarded; boarding.
board (n.1) Look up board at Dictionary.com
Old English bord "a plank, flat surface," from Proto-Germanic *burdam (source also of Old Norse borð "plank," Dutch bord "board," Gothic fotu-baurd "foot-stool," German Brett "plank"), from PIE *bhrdh- "board," from root *bherdh- "to cut." See also board (n.2), with which this is so confused as practically to form one word (if indeed they were not the same word all along).

A board is thinner than a plank, and generally less than 2.5 inches thick. The transferred meaning "food" (late 14c.) is an extension of the late Old English sense of "table" (compare boarder, boarding); hence, also, above board "honest, open" (1610s). A further extension is to "table where council is held" (1570s), then transferred to "leadership council, council (that meets at a table)," 1610s.