The name of several kinds of marsupial animals, found only i n America. The b est known is the common Virginia opossum, found all over the United States. In size it is about as large as a cat, but in shape more like a rat. It has short legs, a very long tail covered with scales instead of hair, except at its base, and a sharp rat-like nose. In some opossums the pouch is absent. In several species the young are carried about on the back of their mother, and with their tails they cling to her tail, which is curved over her back.