(n.) The captain, master, or commander of a ship.

Big Brother OD auditor boss captain chief chief engineer chief mate commander comptroller controller deck officer floor manager floorman floorwalker foreman gaffer ganger head headman inspector master mate monitor naval officer navigating officer navigator noncommissioned officer overman overseer patron pipes proctor quartermaster sailing master second mate shipmaster sirdar skipper slave driver straw boss subforeman super superintendent supervisor surveyor taskmaster the Old Man visitor watch officer