资料来源 : Webster's Revised Unabridged Dictionary (1913)

Rocker \Rock"er\, n.
   1. One who rocks; specifically, one who rocks a cradle.

            It was I, sir, said the rocker, who had the honor,
            some thirty years since, to attend on your highness
            in your infancy.                      --Fuller.

   2. One of the curving pieces of wood or metal on which a
      cradle, chair, etc., rocks.

   3. Any implement or machine working with a rocking motion, as
      a trough mounted on rockers for separating gold dust from
      gravel, etc., by agitation in water.

   4. A play horse on rockers; a rocking-horse.

   5. A chair mounted on rockers; a rocking-chair.

   6. A skate with a curved blade, somewhat resembling in shape
      the rocker of a cradle.

   7. (Mach.) Same as {Rock shaft}.

   {Rocker arm} (Mach.), an arm borne by a rock shaft.

资料来源 : WordNet®

rocker arm
     n : a lever pivoted at the center; used especially to push a
         valve down in an internal-combustion engine [syn: {valve
         rocker}]