\Tid"al\, a.
Of or pertaining to tides; caused by tides; having tides;
periodically rising and falling, or following and ebbing; as,
tidal waters.
      The tidal wave of deeper souls Into our inmost being
      rolls, And lifts us unawares Out of all meaner cares.
                                               --Longfellow.
{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.