lever

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A simple machine consisting of a rigid bar pivoted on a fixed point and used to transmit force, as in raising or moving a weight at one end by pushing down on the other.
2. n. A projecting handle used to adjust or operate a mechanism.
3. n. A means of accomplishing; a tool: used friendship as a lever to obtain advancement.
4. v. To move or lift with or as if with a lever.

Century Dictionary and Cyclopedia

1. n. A simple machine, consisting of a bar or rigid piece of any shape, acted upon at different points by two forces which severally tend to rotate it in opposite directions about a fixed axis. The bearing of this axis is called the fulcrum; of the two forces, one, conceived as something to be balanced or overcome, is termed the resistance, load, or weight, while the other, conceived as voluntarily applied, is termed the power. These are understood to act in the plane of rotation, and each perpendicularly to the line joining the point of its application to the fixed axis. The lengths of these two lines are termed the arms of the lever. If the load is ten times as great as the power, but the power is ten times as far from the fulcrum as the load is from the fulcrum—or, generally, if the two forces are inversely as their respective arms—then the lever is in equilibrium. This principle, beautifully demonstrated by Archimedes, was adopted by Lagrange as one of the two fundamental principles of statics, the other being the principle of the inclined plane. A lever is said to be of the first, second, or third kind, according as of the three points—the fulcrum, the point of application of the load, and that of the power—the first, second, or third is between the other two. But this distinction is insignificant; and when these three points are the vertices of a triangle, and the lever is not in the form of a bar, which often happens, the distinction becomes confused. Among the innumerable examples of levers may be mentioned the steelyard, the crowbar, oars, and the bones of the human limbs.
2. n. In special uses— In surgery, an instrument for applying power, as one of the arms of an obstetrical forceps, used in delivery as a tractor; the vectis.
3. n. In dentistry, an instrument used in extracting the stumps of teeth.
4. n. In a steam-engine, a bar used to control by hand the movement of the engine in starting or reversing it; a starting-bar.
5. n. In firearms, in some forms of breech-loaders, the piece by which the gun is opened or closed, as in the Douglas, Henry, and Maynard rifles. It may be a top, side, or under lever.
6. n. One of the chief supporters of the roof-timber of a house, being itself not a prop, but a part of the framework.
7. n. The lower movable board of a barn-door.
8. n. The first row of a fishing-net.
9. n. Generally, a rod or bar.
10. To act upon, as raising, lowering, etc., with a lever.
11. An obsolete comparative of lief.

Wiktionary

1. adv. obsolete Rather.
2. n. rare A levee.
3. n. 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.
4. n. A small such piece to trigger or control a mechanical device (like a button)
5. n. mechanics A bar, as a capstan bar, applied to a rotatory piece to turn it.
6. n. mechanics An arm on a rock shaft, to give motion to the shaft or to obtain motion from it.
7. v. transitive To move with a lever.
8. v. figuratively (transitive) To use, operate like a lever.
9. v. chiefly UK, finance To increase the share of debt in the capitalization of a business.

GNU Webster's 1913

1. adj. obsolete More agreeable; more pleasing.
2. adv. obsolete Rather.
3. n. (Mech.) 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. Specif., 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.
4. n. A bar, as a capstan bar, applied to a rotatory piece to turn it.
5. n. An arm on a rock shaft, to give motion to the shaft or to obtain motion from it.

WordNet 3.0

1. v. to move or force, especially in an effort to get something open
2. n. a flat metal tumbler in a lever lock
3. n. a simple machine that gives a mechanical advantage when given a fulcrum
4. n. a rigid bar pivoted about a fulcrum