levers

Noun

lever (plural levers)

1. A rigid piece which is capable of turning about one point, or axis (fulcrum), and in which are two or more other points where forces are applied; — used for transmitting and modifying force and motion.
   1. Specifically, a bar of metal, wood or other rigid substance, used to exert a pressure, or sustain a weight, at one point of its length, by receiving a force or power at a second, and turning at a third on a fixed point called a fulcrum. It is usually named as the first of the six mechanical powers, and is of three kinds, according as either the fulcrum F, the weight W, or the power P, respectively, is situated between the other two, as in the figures.
      • Retractable steps and handrails are provided on each side of the cars. The steps, which are under the control of the guard, are operated by hand levers in the entrance vestibule.1952 September, “Modernised Pull-and-Push Trains”, in Railway Magazine, page 617
2. A small such piece to trigger or control a mechanical device (like a switch or a button).
3. A bar, as a capstan bar, applied to a rotatory piece to turn it.
   • A doorknob of whatever roundish shape is effectively a continuum of levers, with the axis of the latching mechanism—known as the spindle—being the fulcrum about which the turning takes place.2012 March, Henry Petroski, “Opening Doors”, in American Scientist, volume 100, number 2, pages 112–3
4. An arm on a rock shaft, to give motion to the shaft or to obtain motion from it.
5. (obsolete, except in generalized senses below) A crowbar.
   • My lord, I brained him with a lever my neighbour lent me, and he stood by and cried, ‘Strike home, old boy!’1613, John Marston, William Barksted, The Insatiate Countess, IV.1

See all 13 meanings of lever