The Collaborative International Dictionary of English v.0.48:

Trygon \Try"gon\ (tr[imac]"g[o^]n), n. [L., a sting ray, from
   Gr.? a kind of fish with a prickle in the tail.] (Zool.)
   Any one of several species of large sting rays belonging to
   Trygon and allied genera.
   [1913 Webster]