A bascule bridge is a type of movable bridge that uses a counterweight to balance the weight of the bridge as it raises and lowers. There are several synonyms for the word "bascule bridge," including drawbridge, lifting bridge, and see-saw bridge. A drawbridge is a type of bascule bridge that is lifted vertically to allow boats and ships to pass underneath. A lifting bridge is similar to a drawbridge but is raised using a hydraulic or mechanical system instead of a counterweight. A see-saw bridge is a type of bascule bridge that pivots on a central point, with one end of the bridge lifting while the other end lowers.