Etymology
Advertisement
big bang (n.)
hypothetical explosive beginning of the universe, developed from the work of astronomers Monsignor Georges Henri Joseph Édouard Lemaître and George Gamow; the phrase is first attested 1950 (said to have been used orally in 1949) by British astronomer Fred Hoyle (1915-2001) in an attempt to explain the idea in laymen's terms.
Related entries & more 
Advertisement
bang (n.)

1540s, "heavy, resounding blow;" see bang (v.). Meaning "loud, sudden explosive noise" is by 1855.

This is the way the world ends
Not with a bang but a whimper
[T.S. Eliot, from "Hollow Men," 1925]
Related entries & more 
bang (v.)

1540s, "to strike hard with a loud blow," an imitative formation, or else from a Scandinavian source akin to Old Norse banga "to pound, hammer" also of echoic origin. Slang meaning "have sexual intercourse with" attested by 1937. As an adverb, "suddenly, abruptly," by 1828, probably from the notion of "with a sudden or violent sound." Related: Banged; banging. Banging (adj.) in the slang sense of "large, great, surpassing in size" is attested by 1864. Bang-up (adj.) "excellent, first-rate, in fine style" (1810) probably is shortened from a phrase such as bang up to the mark.

Related entries & more 
big (adj.)

c. 1300, at first found chiefly in northern England and north Midlands writing, "powerful, strong," of obscure origin, possibly from a Scandinavian source (compare Norwegian dialectal bugge "great man"). Old English used micel (see much) in many of the same senses. It came into general use c. 1400. Meaning "of great size" is late 14c.; that of "full-grown, grown up" is attested from late 14c. Sense of "important, influential, powerful" is from c. 1400. Meaning "haughty, inflated with pride" is from 1570s. Meaning "generous" is U.S. colloquial by 1913.

Big band as a musical style is from 1926. Slang big head "conceit" is first recorded 1850. Big business "large commercial firms collectively" is from 1913 (before that it meant "a profitable income in business"). Big top "main tent of a circus" is from 1895. Big game "large animals hunted for sport" is from 1864. Big house "penitentiary" is U.S. underworld slang first attested 1915 (in London, "a workhouse," 1851). In financial journalism, big ticket items so called from 1956. Big lie is from Hitler's grosse Lüge.

Related entries & more 
gang-bang (n.)
1953, "group sex" (especially many men on one woman or girl, regardless of consent), from gang + bang (v.) in its slang, "perform sexual intercourse" sense. Earlier was gang-shag (1927). Sense of "participate in a street gang" is by 1968. Related: Gang-banger; gang-banging.
Related entries & more 
Advertisement
big-tent (adj.)
in reference to welcoming all sorts and not being ideologically or theologically narrow, American English, 1982 with reference to religion, by 1987 with reference to politics.
Related entries & more 
Big Ben (n.)
clock-bell in the Parliament tower in London, by 1861, generally said to have been named for Sir Benjamin Hall (1802-1867), first Chief Commissioner of Works, under whose supervision the bell was cast. The name later was extended to the clock itself and its tower.
Related entries & more 
Big Brother (n.)
"ubiquitous and repressive but apparently benevolent authority" first recorded 1949, from George Orwell's novel "Nineteen Eighty-Four." The phrase big brother for "older brother" is attested by 1833.
Related entries & more 
big shot (n.)
"important person," 1929, American English, from Prohibition-era gangster slang; earlier in the same sense was great shot (1861). Ultimately a reference to large type of gunshot; see shot (n.).
Related entries & more 
Big Apple (n.)
"New York City," 1909 (but popularized by 1970s tourism promotion campaign), apparently from jazz musicians' use of apple for any city, especially a Northern one.
Related entries & more