mo·men·tum 
(mō-mĕntəm)
(mō-mĕntəm)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.
2.
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.]