lever

Etymology 1

From Middle English lever, levore, levour, from Old French leveor, leveur (“a lifter, lever (also Old French and French levier)”), from Latin levātor (“a lifter”), from levō (“to raise”).

noun

1. (mechanics) A rigid piece which is capable of turning about one point, or axis (the 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.
2. A small such piece to trigger or control a mechanical device (like a button).
3. (mechanics) 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. 2012-03, Henry Petroski, “Opening Doors”, in American Scientist, volume 100, number 2, pages 112–3
4. (mechanics) 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

verb

1. (transitive) To move with a lever.
   With great effort and a big crowbar I managed to lever the beam off the floor.
2. (figurative, transitive) To use, operate or move (something) like a lever (physically).
   Suddenly he had levered himself up from the sofa, rocking the lame man violently, and was walking towards the receptionist. 1961, V. S. Naipaul, A House for Mr Biswas, Vintage International, published 2001, Part Two, Chapter 1
3. (figurative, transitive) To use (something) like a lever (in an abstract sense).
   He was a man who levered his way from small-time communist hack to political power by tapping into the most potent vein of historical juice in the Balkans: nationalism. 9 April 2001, Joshua Cooper Ramo, “Bagging the Butcher”, in Time
   Credited with pioneering the detective novel, Collins has attracted many biographers over the years, drawn to his extraordinary life and work in the hope of levering open a new understanding of the Victorian psyche. 8 December 2013, Robert McCrum, “Biographies of the year — review”, in The Guardian
4. (chiefly UK, finance) To increase the share of debt in the capitalization of a business.
   "The equity holders want you to 'lever up,' use as much debt as you can," said David Stanley, chairman of Kansas City-based Payless Cashways, Jun 26, 1989, “Corporate America wants its privacy”, in Minneapolis Star-Tribune

Etymology 2

From Middle English lever, comparative of leve, leef (“dear, beloved, lief”), equivalent to lief + -er. Related to German lieber (“rather”).

adv

1. (obsolete) Rather.
   for I had lever be without ye / Then have suche besines about ye 1530, John Heywood, The Four PP

Etymology 3

Borrowed from French lever.

noun

1. (rare) A levee.
   We do not appear at Phœbus's Levér. 1742, Miss Robinson, Mrs. Delany's Letters, II.191
   Louis XIV’s day began with a lever at 9 and ended (officially) at around midnight. 21 Sep 2011, Tim Blanning, “The reinvention of the night”, in Times Literary Supplement