o ‧ pos ‧ sum /əˈpɒs ə m $ -ˈpɑː-, ˈpɑːs ə m/ BrE AmE ( also possum ) noun [countable]
[ Date: 1600-1700 ; Language: Virginia Algonquian ; Origin: opassom , from op 'white' + assom 'dog' ]
one of various small animals from America and Australia that have fur and climb trees