lever

lever (lev´ur),

n a bar or rigid body that is capable of turning about one joint or axis and in which are two or more other points where forces are applied. There are three classes of levers, and each has its own most effective use.

lever leverage

n the mechanical advantage gained by the use of a lever. A factor in the magnification of stresses generated by an extension-base partial denture.

lever, second-class,

n a lever in which the force arm is longer than the work-producing arm; thus the work produced is always greater than the energy used, with a resultant high efficiency.

lever, third-class,

n a lever in which the axis is at one end, the load at the other end, and the effort is exerted in between, as in a treadle.