Opossum

opossum, also spelled possum, any of slightly more than 100 species of New World marsupial mammals in the orders Didelphimorphia, Paucituberculata (see rat opossum), and Microbiotheria (see monito del monte). These marsupials, along with their relatives in Australasia, were formerly grouped together in the order Marsupialia (now a cohort including several orders). The word opossum is based on the Algonquian word apasum, meaning “white animal”—in reference to the Virginia opossum of North America. Some Australasian marsupials also are called possums (see phalanger).