'Rocker arm' definitions:

Definition of 'rocker arm'

noun

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

From: GCIDE

Rocker \Rock"er\, n.
1. One who rocks; specifically, one who rocks a cradle. [1913 Webster]
It was I, sir, said the rocker, who had the honor, some thirty years since, to attend on your highness in your infancy. --Fuller. [1913 Webster]
2. One of the curving pieces of wood or metal on which a cradle, chair, etc., rocks. [1913 Webster]
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. [1913 Webster]
4. A play horse on rockers; a rocking-horse. [1913 Webster]
5. A chair mounted on rockers; a rocking-chair. [1913 Webster]
6. A skate with a curved blade, somewhat resembling in shape the rocker of a cradle. [1913 Webster]
7. (Mach.) Same as Rock shaft. [1913 Webster]
Rocker arm (Mach.), an arm borne by a rock shaft. [1913 Webster]