a small, aquatic, egg-laying monotreme mammal (Ornithorhynchus anatinus) of Australia and Tasmania, with webbed feet, a beaverlike tail, and a ducklike bill; duckbill
See platypus in American Heritage Dictionary 4
(plătˈĭ-pəs)
nounpl.plat·y·pus·es
A semiaquatic egg-laying mammal (Ornithorhynchus anatinus) of Australia and Tasmania, having a broad flat tail, webbed feet, and a snout resembling a duck's bill. Also called duckbill, duck-billed platypus.