Boat″swain (�), n. [Boat + swain.] 1. (Naut.) An officer who has charge of the boats, sails, rigging, colors, anchors, cables, cordage, etc., of a ship, and who also summons the crew, and performs other duties.
2. (Zoöl.) (a) The jager gull. (b) The tropic bird.
Boatswain's mate, an assistant of the boatswain. Totten.