Port and starboard vessel's starboard side by green and its port side by red. Aircraft are lit in the same way. Port and starboard Port and starboard are nautical and aeronautical terms of orientation that deal unambiguously with the structure of vessels and aircraft. Their structures are largely bilaterally symmetrical, meaning they have mirror-image left and right halves if divided long-ways down the middle. One asymmetric feature is that on aircraft and ships where access is at the side, this access is usually only provided on the port side. To understand which is which, when a person is facing the bow on a
Port and starboard people are right-handed. 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". The Oxford English Dictionary cites "port" in this usage since 1543. Formerly, "larboard" was often 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