punctuation mark, 1520s as a Latin word, nativized by 1590s, from Latin comma "short phrase or clause of a sentence or line of poetry," from Greek komma "clause in a sentence," also ""stamp, coinage," literally "piece which is cut off," from koptein "to strike, smite, cut off; disable, tire out," which is perhaps from PIE root *kop- "to beat, strike, smite" (see hatchet (n.)), or perhaps Pre-Greek.
Like colon (n.1) and period it was originally a Greek rhetorical term for a part of a sentence, and like them it has been transferred to the punctuation mark that identifies it. In reading aloud the punctuation mark is used to admit small interruptions in continuity of speech for the sake of clarity, but its purpose is to indicate grammatical structure.
university town in England, Middle English Oxforde, from Old English Oxnaforda (10c.) literally "where the oxen ford" (see ox + ford (n.)). In reference to a type of shoe laced over the instep, it is attested from 1721 (Oxford-cut shoes). In reference to an accent supposedly characteristic of members of the university, by 1855. Related: Oxfordian; Oxfordish; Oxfordist; Oxfordy.
Oxford comma for "serial comma" (the second in A, B, and C) is attested by 1990s, from its being used by Oxford University Press or its recommendation by Henry W. Fowler, long associated with Oxford University, in his influential and authoritative book on English usage (1926) in which he writes "there is no agreement at present on the punctuation," but adds that the omission of the serial comma "often leaves readers helpless against ambiguity."
thin sloping line similar to a modern slash, used as a comma in medieval MSS and still in modern text to indicate line breaks in poetry, 1837, from French virgule (16c.), from Latin virgula "punctuation mark," literally "little twig," diminutive of virga "shoot, rod, stick." The word had been borrowed in its Latin form in 1728.