The Collaborative International Dictionary of English v.0.48:

Cyprinodont \Cy*prin"o*dont\ (s?-pr?n"?-d?nt), n. [Gr. ???? kind
   of carp + ????, ????, a tooth.] (Zool.)
   One of the Cyprinodontidae, a family of fishes including
   the killifishes or minnows. See Minnow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cyprinodont
    n 1: any member of the family Cyprinodontidae