1. One that regulates, as:
a. The mechanism in a watch by which its speed is governed.
b. A highly accurate clock used as a standard for timing other clocks.
c. A device used to maintain uniform speed in a machine; a governor.
d. A device used to control the flow of gases, liquids, or electric current.
2. One, such as the member of a governmental regulatory agency, that ensures compliance with laws, regulations, and established rules: banking regulators; price regulators.
3. A substance that affects the amount of product or the progress of a biochemical reaction or process: a regulator of embryogenesis.
4. See regulator gene.
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.