im·pe·tus 
/ˈɪmpətəs/ noun
/ˈɪmpətəs/ noun 1 : a force that causes something (such as a process or activity) to be done or to become more active [noncount] ▪ His discoveries have given impetus to further research. ▪ The movement is now gaining/losing impetus. [=momentum] [singular] ▪ Her work provided the major impetus [=stimulus] behind the movement. — often + for ▪ The tragic accident became an impetus for changing the safety regulations. — sometimes followed by to + verb ▪ His discoveries have given researchers the impetus to try something new. 2 [noncount] technical : a force that causes an object to begin moving or to continue to move
