Didelphous \Di*del"phous\, a. (Zo["o]l.) Didelphic. Didelphous \Di*del"phous\, n. [NL. See {Didelphia}.] (Zo["o]l.) Formerly, any marsupial; but the term is now restricted to an American genus which includes the opossums, of which there are many species. See {Opossum}. [Written also {Didelphis}.] See Illustration in Appendix. --Cuvier.