- rocker (n.)
- "a rocking chair," 1852, American English, from rock (v.); earlier "nurse charged with rocking a cradle" (c.1400). In sense of "one of the curved pieces of wood that makes a chair or cradle rock" it dates from 1787. Slang off (one's) rocker "crazy" first recorded 1897. Meaning "one who enjoys rock music" (as opposed to mod) is recorded from 1963.