The Collaborative International Dictionary of English v.0.48:

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.
   [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]

WordNet (r) 3.0 (2006):

tidal
    adj 1: of or relating to or caused by tides; "tidal wave"

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "tidal":
   affluent, aquatic, balneal, confluent, coursing, decurrent,
   deep-sea, defluent, diffluent, estuarine, flowing, fluent,
   fluxional, fluxive, grallatorial, gulfy, gushing, littoral, mazy,
   meandering, natant, natatorial, natatory, pouring, profluent,
   racing, running, rushing, seashore, serpentine, shore, sluggish,
   streaming, surging, surgy, swimming, vortical, water-dwelling,
   water-growing, water-living, water-loving



Easton's 1897 Bible Dictionary:

Tidal
   (in the LXX. called "Thorgal"), styled the "king of nations"
   (Gen.14:1-9). Mentioned as Tudkhula on Arioch's brick (see
   facing page 139). _Goyyim_, translated "nations," is the country
   called Gutium, east of Tigris and north of Elam.


Hitchcock's Bible Names Dictionary (late 1800's):

Tidal, that breaks the yoke; knowledge of elevation