Bascule /(băs"kū̇l)/

Bas·cule

Bascule

n.
  1. In mechanics, an apparatus on the principle of the seesaw, in which one end rises as the other falls.

Phrases & Compounds
Bascule bridge
a counterpoise or balanced drawbridge, which is opened by sinking the counterpoise and thus lifting the footway into the air.