tidal wave

noun6

1. •
   (nonstandard) A large, sudden, and disastrous wave of water caused by a tremendous disturbance in the ocean; a tsunami. (See Usage notes below.)

   • The last tidal wave here killed twenty and left thousands homeless.
2. •
   (nonstandard) A large, sudden inundation of water from the storm surge, or waves of that surge; a sudden surge of river water.
3. •
   (figurative) A sudden and powerful surge.

   • As the doors opened, a tidal wave of people flooded into the room.
   • I was overcome by a tidal wave of emotions.
4. •
   A large and sudden rise and fall in the tide.
5. •
   A crest of ocean water resulting from tidal forces.
6. •
   (no longer used) A crest of ocean water; a wave.