momentum

n.; pl. L. Momenta F. Momentums [ L. See Moment. ] 1. (Mech.) The quantity of motion in a moving body, being always proportioned to the quantity of matter multiplied by the velocity; impetus. [ 1913 Webster ]

2. Essential element, or constituent element. [ 1913 Webster ]

I shall state the several momenta of the distinction in separate propositions. Sir W. Hamilton. [ 1913 Webster ]

3. A property of an activity or course of events, viewed as analogous to forward motion or to physical momentum (def. 1), such that the activity is believed to be able to continue moving forward without further application of force or effort; -- often used to describe an increase in the acquisition of public support for a purpose; as, as, the petition drive gained momentum when it was mentioned in the newspapers. [ PJC ]