(mechanics) A rigid piece used for transmitting and modifying force and motion, typically a bar of metal or wood that exerts pressure or sustains weight at one point by receiving force or power at another point and turning on a fixed fulcrum.

A small such piece to trigger or control a mechanical device (like a button).

(mechanics) A bar, as a capstan bar, applied to a rotatory piece to turn it.

(mechanics) An arm on a rock shaft, to give motion to the shaft or to obtain motion from it.

(rare) A levee.

(transitive) To move with a lever.

(figurative, transitive) To use, operate or move (something) like a lever (physically).

(figurative, transitive) To use (something) like a lever (in an abstract sense).

(chiefly UK, finance) To increase the share of debt in the capitalization of a business.