Brewer's: Starboard and Larboard
Star-is the Anglo-Saxon steor, rudder, bord, side; meaning the right side of a ship (looking forwards). Larboard is now obsolete, and “port” is used instead. To port the helm is to put the helm to the larboard. Byron, in his shipwreck (Don Juan), says of the ship -
She gave a heel [i.e. turned on one side], and then a lurch to port, And going down head foremost, sunk, in short.