possum

from WordNet (r) 3.0 (2006)

possum
    n 1: nocturnal arboreal marsupial having a naked prehensile tail
         found from southern North America to northern South America
         [syn: {opossum}, {possum}]
    2: small furry Australian arboreal marsupials having long
       usually prehensile tails [syn: {phalanger}, {opossum},
       {possum}]

from The Collaborative International Dictionary of English v.0.48

Opossum \O*pos"sum\, n. [Of N. American Indian origin.] (Zool.)
   Any American marsupial of the genera {Didelphys} and
   {Chironectes}; called also {possum}. The common species of
   the United States is {Didelphys Virginiana}.
   [1913 Webster]

   Note: Several related species are found in South America. The
         water opossum of Brazil ({Chironectes variegatus}),
         which has the hind feet, webbed, is provided with a
         marsupial pouch and with cheek pouches. It is called
         also {yapock}.
         [1913 Webster]

   {Opossum mouse}. (Zool.) See {Flying mouse}, under {Flying}.
      

   {Opossum shrimp} (Zool.), any schizopod crustacean of the
      genus {Mysis} and allied genera. See {Schizopoda}.
      [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Possum \Pos"sum\, n. [Shortened from opossum.] (Zool.)
   An opossum. [Colloq. U. S.]
   [1913 Webster]

   {To play possum}, {To act possum}, to feign ignorance,
      indifference or inattention, with the intent to deceive;
      to dissemble; -- in allusion to the habit of the opossum,
      which feigns death when attacked or alarmed.
      [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

29 Moby Thesaurus words for "possum":
      Cape polecat, ape, bar, bear, cavy, chimp, chimpanzee, coon,
      ferret, foumart, glutton, groundhog, guinea pig, hedgehog, monk,
      monkey, mousehound, opossum, polecat, porcupine, prairie dog,
      quill pig, raccoon, skunk, weasel, whistle-pig, wolverine,
      woodchuck, zoril