The term 'pulley part' can refer to two different components of a pulley system, which is a type of simple machine used to lift or move heavy objects. The first component is a BELT, which is a loop of flexible material that is used to transfer power from one pulley to another. The second component is a ROPE, which is a length of strong, durable material that is used to connect the pulleys and provide tension. Both the BELT and the ROPE are essential parts of a pulley system.