1690s, originally an art criticism term, "assemblage of figures or objects forming a harmonious whole in a painting or design," from French groupe "cluster, group" (17c.), from Italian gruppo "group, knot," which probably is, with Spanish grupo, from a Germanic source, from Proto-Germanic *kruppaz "round mass, lump," part of the general group of Germanic kr- words with the sense "rounded mass" (such as crop (n.).
Extended to "any assemblage, a number of individuals related in some way" by 1736. Meaning "pop music combo" is from 1958. As it was borrowed after the Great Vowel Shift in English, the pronunciation of the -ou- follows French rather than English models.
early 13c., "act of engaging in combat," verbal noun from fight (v.). Old English had feohtlac (n.) "fighting, battle." Nautical fighting-top "platform near the top of a mast for small-arms fire" is from 1890.
"qualified or trained to fight," mid-14c., present-participle adjective from fight (v.). Fighting chance is from 1877; fighting mad is attested by 1750; fighting words is by 1882. Fighty "pugnacious" is attested from c. 1200.
1816, in pugilism, the practice of getting at close quarters with an opponent; see in + fighting. Old English infiht (n.) meant "brawl within a house or between members of a household." Middle English had infight (v.) "to attack" (c. 1300); the modern verb infight "fight at close quarters" (1916) appears to be a back-formation from in-fighting. Related: In-fighter (1812).
mid-15c., cokfytyng, match or contest between cocks (see cock (n.1)). Cock-fight (n.) is from 1560s.