nocturnal, omnivorous American marsupial mammal, c. 1600, from Powhatan (Algonquian) opassum, "equivalent to a proto-Algonquian term meaning 'white dog'" [Bright]. The colloquial form is possum (q.v.).

American marsupial mammal, 1610s, shortened form of opossum (q.v.). It is nocturnal, omnivorous, and when caught or threatened with danger feigns death; hence the phrase play possum "feign death when threatened," attested by 1822.