∙ The punctuation mark ⟨,⟩ used to indicate a set off parts of a sentence or between elements of a list. typography
∙ A similar-looking subscript diacritical mark. Romanian typography
∙ A European and North American butterfly, Polygonia c-album, of the family Nymphalidae.
∙ a difference in the calculation of nearly identical intervals by different ways. music
∙ A delimiting marker between items in a genetic sequence. genetics
∙ In Ancient Greek rhetoric a comma (κόμμα) is a short clause, something less than a colon, originally denoted by comma marks. In antiquity comma was defined as a combination of words that has no more than eight syllables. This term is later applied to longer phrases, e.g. the Johannine comma.