- marsupial [mär so͞o′pē əl]adj.1. of or like a marsupium, or pouch2. of a superorder (Marsupialia) of mammals that lack a placenta and have an external abdominal pouch (marsupium) containing the teats: the incompletely developed offspring nurses within this pouch for several months after birth to complete its developmentn.an animal of this kind, as a kangaroo, opossum, or wombat
English World dictionary. V. Neufeldt. 2014.