Port (nautical)
Port is a nautical term referring to the left-hand side of a ship when facing towards the bow. The terms are also used for aircraft, spacecraft, and analogous vessels. The equivalent for the right-hand side is "starboard".
A port buoy is a lateral buoy used to guide vessels through channels or close to shallow water. The port buoy is one that a vessel must leave to port when passing upstream.
An archaic version of the term is larboard. The term larboard, when shouted in the wind, was presumably too easy to confuse with starboard, and so the word port came to replace it, reffering to the side of the ship where cargo is loaded from the port.