The term JIB can refer to two different things. The first is a type of SAIL, which is a four-letter word. A jib is a triangular SAIL that is set at the front of a boat and is used to help steer the vessel. The second is a five-letter word, BAULK, which is a nautical term for an obstruction or barrier in the water. Baulks are often used to protect ships from running aground or to create a safe passage for vessels.