'Starboard' is Old English for 'steering-side' — ships were steered from the right.
The right-hand side of a ship or aircraft when facing forward.
From Old English 'stēorbord,' a compound of 'stēor' (rudder, steering paddle) and 'bord' (side of a ship, board). Before the invention of the stern-mounted rudder in the twelfth century, European ships were steered with a large paddle mounted on the right side of the vessel. The steersman stood on the right, operating this 'steering board,' and the entire right side of the ship became known as the 'steer-board side.' The left side was called 'port' (originally 'larboard') because ships docked with their left side against the port, protecting the delicate steering paddle on the right from being crushed. Key
The reason 'port' replaced the older term 'larboard' (from Old English 'bæcbord,' back-board) for the left side of a ship was safety: 'larboard' sounded too much like 'starboard' when shouted in a storm. The British Admiralty officially mandated 'port' in 1844 to prevent potentially fatal confusion.