The United States Navy occupational rating of boatswain's mate is a designation given by the Bureau of Naval Personnel (BUPERS) to enlisted members who were rated or "striking" for the rating as a deck seaman. The colloquial form of address for a boatswain's mate is "Boats".

A boatswain, bo's'n, bos'n, or bosun, also known as a deck boss, or a qualified member of the deck department, is the most senior rate of the deck department and is responsible for the components of a ship's hull. The boatswain supervises the other members of the ship's deck department, and typically is not a watchstander, except on vessels with small crews. Additional duties vary depending upon ship, crew, and circumstances.