The term 'STOP, AT SEA' can be broken down into four crossword solutions: BELAY (5 letters), AVAST (5 letters), LAYTO (5 letters), and HEAVETO (7 letters). BELAY is a nautical term meaning to secure a rope or cable by winding it around a cleat or belaying pin. AVAST is an interjection used to express surprise or to command someone to stop. LAYTO is a nautical term meaning to bring a ship to a stop, usually by turning the bow into the wind. HEAVETO is a nautical term meaning to turn a ship's bow away from the wind in order to reduce speed.