Source : Webster's Revised Unabridged Dictionary (1913)

Tidal \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.

Source : WordNet®

tidal basin
     n : a basin that is full of water at high tide