n.1. One that rocks, as:
a. A rocking chair.
b. A rocking horse.
2. One of the two curved pieces upon which a cradle, rocking chair, or similar device rocks.
3. A cradle used for washing or panning ores.
4. A small curved blade with a toothed edge used in mezzotint engraving to roughen the surface of the metal plate.
5. An object having a curved form, as the keel of a ship or a skate blade sharpened in a curve.
6. A curved stripe at the bottom part of a chevron worn by noncommissioned officers above the rank of sergeant.
7. Music a. A rock song, singer, or musician.
b. A fan of rock music.