<P> Port and starboard are nautical and aeronautical terms for left and right, respectively . Port is the left - hand side of a vessel or aircraft, facing forward . Starboard is the right - hand side, facing forward . Since port and starboard never change, they are unambiguous references that are not relative to the observer . </P> <P> The term starboard derives from the Old English steorbord, meaning the side on which the ship is steered . Before ships had rudders on their centrelines, they were steered with a steering oar at the stern of the ship and, because more people are right - handed, on the right - hand side of it . Since the steering oar was on the right side of the boat, it would tie up at the wharf on the other side . Hence the left side was called port . </P> <P> Formerly, larboard was used instead of port . This is from Middle - English ladebord and the term lade is related to the modern load . Larboard sounds similar to starboard and in 1844 the Royal Navy ordered that port be used instead . The United States Navy followed suit in 1846 . Larboard continued to be used well into the 1850s by whalers . </P> <P> The navigational treaty convention, the International Regulations for Preventing Collisions at Sea--for instance, as appears in the Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations of 1996 (and comparable US documents from the US Coast Guard),--sets forth requirements for maritime vessels to avoid collisions, whether by sail or powered, and whether a vessel is overtaking, approaching head - on, or crossing . To set forth these navigational rules, the terms starboard and port are absolutely essential, and to aid in in situ decision - making, the two sides of each vessel are marked, dusk to dawn, by navigation lights, the vessel's starboard side by green and its port side by red . Aircraft are lit in the same way . </P>

Where did the terms port and starboard come from