What does the word impetus mean?

Usage examples for impetus

  1. His popularity, as yet, was mainly due to a general detestation of the rule he had replaced; but such a sentiment gives to a new sovereign an impetus which, if he knows how to use it, will carry him a long way toward success; and among those in the Duke's confidence it was rumoured that he was qualified not only to profit by the expectations he had raised but to fulfil them. – The Valley of Decision by Edith Wharton
  2. Indeed, the impetus that was given, by the effects of the shadow, in this way, to humanity in gross, was quite as remarkable as were its contrary tendencies on humanity in detail. – The Monikins by J. Fenimore Cooper