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.
a. A rock song, singer, or musician.
b. A fan of rock music.
off (one's) rocker Slang
Out of one's mind; crazy.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.