Meaning : An overwhelming manifestation of some emotion or phenomenon.
Example :
A tidal wave of nausea.
The flood of letters hit him with the force of a tidal wave.
A tidal wave of crime.
Meaning : An unusual (and often destructive) rise of water along the seashore caused by a storm or a combination of wind and high tide.
Meaning : A wave resulting from the periodic flow of the tides that is caused by the gravitational attraction of the moon and sun.