Other forms: momenta
Momentum is the moving power a thing carries — mass times speed. Gather momentum, lose momentum, keep the momentum going.
In physics it is conserved absolutely: the total before a collision equals the total after, which is why rockets work at all — throw mass backwards and you go forwards. The figurative sense is now commoner and means a campaign that is hard to stop.
1nounmomentumThe moving power a thing carries.
“The truck was going so fast that its momentum carried it straight through the fence.”
momentum is a physical quantity.
Latin momentum means movement or a moment, a contraction of movimentum, from movere, to move. Moment and movement are the same word.
Latin
mōmentum
English, today
momentum
Borrowed from Latin mōmentum. a doublet of moment and movement.
Etymology from Wiktionary, CC BY-SA