comma (n.)
1520s as a Latin word, nativized by 1590s, from Latin comma "short phrase," from Greek komma "clause in a sentence," literally "piece which is cut off," from koptein "to cut off," from PIE root *kop- "to beat, strike" (see hatchet (n.)). Like colon (n.1) and period, 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.