force that increases the rate of development of a process; impetus 动力; 冲力; 势头: The movement to change the union's constitution is slowly gathering momentum. 修改工会宪章的运动正慢慢加强. 
(physics 物) quantity of motion of a moving object, measured as its mass multiplied by its velocity 动量: The sledge gained momentum as it ran down the hill. 雪橇从山上下冲时动量越来越大.