Source : Webster's Revised Unabridged Dictionary (1913)

Alluvial \Al*lu"vi*al\, n.
   Alluvial soil; specif., in Australia, gold-bearing alluvial
   soil.

Alluvial \Al*lu"vi*al\, a. [Cf. F. alluvial. See {Alluvion}.]
   Pertaining to, contained in, or composed of, alluvium;
   relating to the deposits made by flowing water; washed away
   from one place and deposited in another; as, alluvial soil,
   mud, accumulations, deposits.

Source : WordNet®

alluvial
     adj : of or relating to alluvium