tidal wave noun definition in Coastlines and the sea topic from the Oxford Advanced Learner's Dictionary

tidal wave

 noun: Coastlines and the sea topic
1 a very large ocean wave that is caused by a storm or an earthquake, and that destroys things when it reaches the land According to one account, the explosion caused a tidal wave 65 feet high. 2 tidal wave (of something) a sudden increase in a particular feeling, activity or type of behaviour a tidal wave of crime