coxswain: [15] A coxswain was originally a servant, or swain, whose job was to steer a ship’s boat, or cock (cock comes from Old French coque, which was probably a descendant via late Latin caudica ‘canoe’ of Latin caudex ‘tree trunk’, and swain is a borrowing from Old Norse sveinn ‘boy, servant’). The abbreviation cox seems to have developed in the 19th century.
early 14c., "officer in charge of a ship's boat and its crew," from cock "ship's boat" (from Old French coque "canoe") + swain "boy," from Old Norse sveinn "boy, servant" (see swain).