The starboard is the right side of a boat or plane. You can also say that anything on the right side of a ship is starboard.
This word has to do with direction, specifically direction on a ship. The word originated with sea vessels whose right side was used for steering. Since the stars helped sailors determine direction, this part of the ship became known as the starboard. You can also use starboard as an adjective for anything on the right side of a ship. If you ever ride on a boat, you could probably impress the captain by talking about equipment on the starboard side.