資料來源 : Webster's Revised Unabridged Dictionary (1913)

Lever \Le"ver\ (l[=e]"v[~e]r or l[e^]v"[~e]r; 277), n. [OE.
   levour, OF. leveor, prop., a lifter, fr. F. lever to raise,
   L. levare; akin to levis light in weight, E. levity, and
   perh. to E. light not heavy: cf. F. levier. Cf. {Alleviate},
   {Elevate}, {Leaven}, {Legerdemain}, {Levee}, {Levy}, n.]
   1. (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.

   2. (Mach.)
      (a) A bar, as a capstan bar, applied to a rotatory piece
          to turn it.
      (b) An arm on a rock shaft, to give motion to the shaft or
          to obtain motion from it.

   {Compound lever}, a machine consisting of two or more levers
      acting upon each other.

   {Lever escapement}. See {Escapement}.

   {Lever jack}. See {Jack}, n., 5.

   {Lever watch}, a watch having a vibrating lever to connect
      the action of the escape wheel with that of the balance.
      

   {Universal lever}, a machine formed by a combination of a
      lever with the wheel and axle, in such a manner as to
      convert the reciprocating motion of the lever into a
      continued rectilinear motion of some body to which the
      power is applied.