mono·​treme | \ ˈmä-nə-ˌtrēm How to pronounce monotreme (audio) \

Definition of monotreme

: 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 Content includes video, images, and questions designed to teach students about mammals, birds, primates, bears, reptiles, monotremes, marsupials and others. Tracy Maness, Houston Chronicle, 6 Apr. 2020 Males of the Australian monotremes — egg-laying mammals — produce venom in their thighs during mating season and deliver the poison to competitors via hollow spurs just above their webbed feet. 8. Gemma Tarlach, Discover Magazine, 25 Sep. 2018 The platypus is part of a small group of animals called monotremes, which lay eggs and produce milk to feed their young. Maria Clark,, 19 Mar. 2018 Around 80 million years later, the monotremes—or egg-laying mammals—split off from the mammalian lineage, says Rebecca Young, a biologist at the University of Texas at Austin. National Geographic, 30 July 2016 There are three kinds of mammals: egg-laying monotremes such as the platypus, marsupials like kangaroos and opossums, and the majority—placental, or eutherian, mammals—including humans and about 4400 other mammal species. Elizabeth Pennisi, Science | AAAS, 19 June 2017 Though monotremes' fossil record is limited, some skulls have been found, such as the extinct Obdurodon dicksoni. National Geographic, 30 July 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'monotreme.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of monotreme

1835, in the meaning defined above

History and Etymology for monotreme

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

Learn More About monotreme

Time Traveler for monotreme

Time Traveler

The first known use of monotreme was in 1835

See more words from the same year

Dictionary Entries Near monotreme




See More Nearby Entries 

Statistics for monotreme

Cite this Entry

“Monotreme.” Dictionary, Merriam-Webster, Accessed 20 Jan. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for monotreme


mono·​treme | \ ˈmä-nə-ˌtrēm How to pronounce monotreme (audio) \

Kids Definition of monotreme

: any of a small group of egg-laying mammals that includes the platypus


mono·​treme | \ ˈmän-ə-ˌtrēm How to pronounce monotreme (audio) \

Medical Definition of monotreme

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

More from Merriam-Webster on monotreme Encyclopedia article about monotreme


Test Your Vocabulary

Name that Thing: Flower Edition

True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!