n.

1. 抽搐，惊厥[P1]
   The child's convulsions filled us with fear.

   孩子抽筋使我们忧心忡忡。

2. 大笑，狂笑[P1]
   The story was so funny that we were all in convulsions.

   那个故事真滑稽，引得我们捧腹大笑。

3. 震动；动乱；（地震等）灾变[C]

n.

1. a sudden, violent, irregular movement of the body caused by involuntary contraction of muscles.
2. (convulsions) uncontrollable laughter.
3. a violent social or natural upheaval.