noun Download 🔗Share A semi-aquatic, egg-laying monotreme mammal with a bill resembling that of a duck, that has a mole-like body, a tail resembling that of a beaver, a waterproof pelt, and flat webbed feet — males have poisonous spurs on the inside of the back legs; Ornithorhynchus anatinus Examples : "While hiking near the Australian river, we were lucky enough to spot a platypus swimming, its duck-like bill visible above the water. " animal organism nature biology anatomy physiology environment Chat with AIVocabulary GamePractice Reading