im·pe·tus/`ɪmpətəs; ˈɪmpɪtəs/ n [U] 1 an influence that makes something happen or happen more quickly 推动力,促进因素: Public protest has provided the impetus for reform. 公众抗议为改革提供了推动力。 2technical a force that makes an object start moving, or keeps it moving 【术语】 〔使物体移动的〕动力,冲力