Yours, Etc.: Origins and Uses of 8 Sign-Offs
surname, from early 16c., earlier Cocks (c.1300), in many cases from cock (n.1), which apparently was used as a personal name in Old English, also as a familiar term for a boy, later used of apprentices, servants, etc. Perhaps in some cases for the sign of an inn. In some cases perhaps from cook (n.), or Welsh coch "red."