If something roars, it makes a very loud noise.咆哮; 轰鸣The engine roared, and the vehicle leapt forward. 引擎轰鸣,车子猛地向前驶去。
When a lion roars, it makes the loud sound that lions typically make.(狮子) 吼叫The lion roared once, and sprang. 狮子吼了一声,跳了起来。