n. pl. mo·men·ta (-tə) or mo·men·tums
1. Symbol p Physics A quantity used to measure the motion of a body, equal to the product of the body's mass and its velocity. Also called linear momentum.
a. The force or energy exhibited by a moving body: The ball did not have enough momentum to reach the goalposts.
b. The driving force or advancing strength of a development or course of events: The effort to reform public education has been gaining momentum.
3. Philosophy An essential or constituent element; a moment.
[Latin mōmentum, movement, from *movimentum, from movēre, to move; see meuə- in the Appendix of Indo-European roots.]
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.