a. Of or pertaining to tides; caused by tides; having tides; periodically rising and falling, or following and ebbing; as, tidal waters. [ 1913 Webster ]

The tidal wave of deeper souls
Into our inmost being rolls,
And lifts us unawares
Out of all meaner cares. Longfellow. [ 1913 Webster ]

Tidal air (Physiol.), the air which passes in and out of the lungs in ordinary breathing. It varies from twenty to thirty cubic inches. --
Tidal basin, a dock that is filled at the rising of the tide. --
Tidal wave. (a) See Tide wave, under Tide. Cf. 4th Bore. (b) A vast, swift wave caused by an earthquake or some extraordinary combination of natural causes. It rises far above high-water mark and is often very destructive upon low-lying coasts. [ 1913 Webster ]

n. 1. an unusually high wave from the sea, sometimes reaching far inland and causing great destruction, and usually caused by some event, such as an earthquake, far from the shore. In Japan, such a wave is called a tsunami. [ PJC ]

2. [ fig. ] an unusually large quantity of items or events requiring attention and causing strain on the capacity to handle them; as, a tidal wave of orders for a new product; a tidal wave of tourists. [ PJC ]