The Collaborative International Dictionary of English v.0.48:

Cowrie \Cow"rie\ Cowry \Cow"ry\(kou"r[y^]), n.; pl. Cowries
   (-r[i^]z). [Hind. kaur[imac].] (Zool.)
   A marine shell of the genus Cypr[ae]a.
   [1913 Webster]

   Note: There are numerous species, many of them ornamental.
         Formerly Cypr[ae]a moneta and several other species
         were largely used as money in Africa and some other
         countries, and they are still so used to some extent.
         The value is always trifling, and varies at different
         places.
         [1913 Webster]

WordNet (r) 3.0 (2006):

cowry
    n 1: any of numerous tropical marine gastropods of the genus
         Cypraea having highly polished usually brightly marked
         shells [syn: cowrie, cowry]