ETYM Latin comma part of a sentence, comma, Greek koma clause. Related to Capon.
1. A punctuation mark (,) used to indicate the separation of elements within the grammatical structure of a sentence.
2. Anglewing butterfly with a comma-shaped mark on the underside of each hind wing; SYN. comma butterfly, Polygonia comma.
Punctuation mark (), most commonly used to mark off a phrase or noun in apposition, mark off a subordinate clause or phrase, or separate items in a list.
Some writers, uncertain where sentences properly end, use a comma instead of a full stop (period), writing We saw John last night, it was good to see him again, rather than We saw John last night. It was good to see him again. The meaning is entirely clear in both cases. One solution in such situations is to use a semicolon (;), which bridges the gap between the close association of the comma and the sharp separation of the period. For parenthetical commas, see parenthesis.