A rigid bar pivoted about a fulcrum is a lever, which is a simple machine used to amplify force. The term 'PIVOT' refers to the point at which the lever rotates around, which is known as the fulcrum. The force applied to the lever is called the effort, while the force produced by the lever is called the load. The efficiency of the lever depends on the distance between the effort and the fulcrum, as well as the distance between the load and the fulcrum. The answer to the crossword clue is 'PIVOT'.'