monotreme

noun

mono·​treme ˈmä-nə-ˌtrēm 

: any of an order (Monotremata) of egg-laying mammals comprising the platypuses and echidnas

Examples of monotreme in a Sentence

Recent Examples on the Web

Their mammary glands are markedly different from those of eutherian mammals such as cows and humans that have nipples; monotremes instead secrete milk through specialized mammary hairs. —Gat Rauner, The Conversation, 13 Aug. 2024

And both echidnas and platypuses are considered monotremes. —Paul Smaglik, Discover Magazine, 29 May 2024

Why did those teeth end up disappearing altogether in modern monotremes? —Elizabeth Rayne, Ars Technica, 7 June 2024

While the ancestors of today’s monotremes had teeth, the living species do not and instead grind their food inside their mouths. —Sarah Kuta, Smithsonian Magazine, 13 June 2024

Word History

Etymology

New Latin Monotremata, from Greek mon- + trēmat-, trēma hole — more at trematode

First Known Use

1835, in the meaning defined above

Kids Definition

monotreme

noun

mono·​treme ˈmän-ə-ˌtrēm 

: any of an order of egg-laying mammals that include the platypuses and echidnas

Medical Definition

monotreme

noun

mono·​treme ˈmän-ə-ˌtrēm 

: any mammal (as a platypus) of the order Monotremata