mon·o·treme
noun/ˈmɒnətriːm/
/ˈmɑːnətriːm/
(specialist)- a class of animal including the echidna and the platypus, that lays eggs, but also gives milk to its babies
Topics Animalsc2单孔目动物(卵生哺乳动物) Word Originmid 19th cent.: from mono- ‘single’ + Greek trēma ‘hole’.