roar             
 verb uk/rɔːr/ us/rɔːr/
C2 [ I ]吼叫;咆哮 
to make a long, loud, deep sound
  We could hear the lions roaring at the other end of the zoo. 我们可以听到狮子在动物园的另一端咆哮。 
  [ I ](车辆或飞机)呼啸而行 
If a vehicle or aircraft roars somewhere, it moves there very quickly making a lot of noise.
  She looked up as a plane roared overhead. 一架飞机轰鸣着掠过她的头顶,她抬头张望。 
 The street was full of boys roaring up and down on their motorbikes. 大街上到处是些年轻小伙子骑着摩托车来回呼啸而过。 
 C2 [ T ]大声地说;叫喊 
to shout loudly
  [ + speech ] "Stop that!" he roared. “住手!”他大吼道。 
 - More examples
 - A cloud of dust rose in the air as the car roared past.
 - The monster roared and gnashed its teeth.
 - The lion opened its jaws and roared.
 - The plane roared overhead and went into a nosedive.
 - She roared with laughter .
 
Phrasal verb   
roar with something 因…大叫;放声(大笑);高声(怒吼)
to express an emotion, such as laughter or anger, noisily
  She roared with laughter when she saw what he was wearing. 看到他的一身穿戴,她哈哈大笑起来。 
 roar       
noun [ C or S ] uk/rɔːr/ us/rɔːr/
C2 吼叫;呼啸;咆哮
a loud, deep sound
  The lion let out a loud roar. 狮子发出一声吼叫。 
 His apartment was on a main road and there was a constant roar of traffic. 他的公寓在一条大马路旁边,轰鸣的车辆声不绝于耳。