On a boat, the opposite of port is starboard. "Port" refers to the left side of the boat when facing forward, while "starboard" refers to the right side of the boat when facing forward. These nautical terms are used to avoid confusion when giving directions or maneuvering the boat. Another way to remember this is that "port" and "left" both have four letters, while "starboard" and "right" are longer words with more letters.