"an animal of the class Mammalia; an animal that suckles its young," 1826, Englished form of Modern Latin Mammalia (1773), coined 1758 by Linnaeus for that class of animals from neuter plural of Late Latin mammalis "of the breast," from Latin mamma "breast," which is cognate with mamma. With the exception of a few egg-laying species, all bear live young and have the mammary gland for the young to suck. All also are warm-blooded and breathe air. In Middle English, mammille was "a woman's breast" (early 15c.).
large, aquatic herbivorous mammal of the Indian Ocean and western Pacific, 1800 (by 1789 in French), from Malay (Austronesian) duyung, which is dugung in the Philippines.
nocturnal, omnivorous American marsupial mammal, c. 1600, from Powhatan (Algonquian) opassum, "equivalent to a proto-Algonquian term meaning 'white dog'" [Bright]. The colloquial form is possum (q.v.).
fictional two-headed mammal from "Dr. Dolittle" (1922), coined by Hugh Lofting from the expressions push me, pull you. Popularized by the 1967 film version of the book.