A possum (plural form: possums) is any of about 70 small- to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi (and introduced to New Zealand and China). The name derives from their resemblance to the opossums of the Americas (the name is from Algonquian wapathemwa, not Greek or Latin, so the plural is possums, not possa or possi).