The Collaborative International Dictionary of English v.0.48:

Siluroid \Si*lu"roid\, n. [Silurus + -oid.] (Zool.)
   Belonging to the Siluroidei, or Nematognathi, an order of
   fishes including numerous species, among which are the
   American catfishes and numerous allied fresh-water species of
   the Old World, as the sheatfish (Silurus glanis) of Europe.
   -- n. A siluroid fish.
   [1913 Webster]