n.1 a any mainly tree-living marsupial of the family Didelphidae, native to America, having a prehensile tail and hind feet with an opposable thumb. b (in full water opossum) an opossum, Chironectes minimus, suited to an aquatic habitat and having webbed hind feet. Also called YAPOK.
2 Austral. & NZ POSSUM 2.
Etymology: Virginian Ind. apassum