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.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.n. In dentistry, an instrument used in extracting the stumps of teeth.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.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.n. One of the chief supporters of the roof-timber of a house, being itself not a prop, but a part of the framework.n. The lower movable board of a barn-door.n. The first row of a fishing-net.n. Generally, a rod or bar.To act upon, as raising, lowering, etc., with a lever.An obsolete comparative of lief.