am·​ni·​ote ˈam-nē-ˌōt How to pronounce amniote (audio)
: any of a group (Amniota) of vertebrates that undergo embryonic or fetal development within an amnion and include the birds, reptiles, and mammals
amniote adjective

Examples of amniote in a Sentence

Recent Examples on the Web The fossils are a kind of milepost for when amniotes were settling in on land and establishing the foundational traits of later creatures like fuzzy mammals and feathery dinosaurs. Riley Black, Smithsonian Magazine, 11 Jan. 2024 Described Thursday in Current Biology, these tatters of fossil skin and various skin impressions come from some of the earliest amniotes. Riley Black, Smithsonian Magazine, 11 Jan. 2024 During the Carboniferous Period, the evolutionary adaption of the amniote egg allowed the early tetrapods to lay their eggs on land — allowing the species to transition to a fully on-land lifestyle, according to the University of California Museum of Paleontology. Elizabeth Gamillo, Discover Magazine, 11 Jan. 2024 The solution to land's dry nature was to encase eggs in a number of membrane layers, in what is now known as an amniote egg. Christie Wilcox, Discover Magazine, 28 July 2012 The tumor that afflicted a poor Pappochelys some 240 million years ago is the oldest evidence of this type of cancer in an amniote, a lineage of four-limbed vertebrates, or tetrapods, that includes reptiles, birds and mammals. Gemma Tarlach, Discover Magazine, 7 Feb. 2019 The fossilized critter is an amniote—a land-dwelling vertebrate that lays eggs— and has four legs. Rasha Aridi, Smithsonian Magazine, 11 Nov. 2021 This fossil appears to be an early amniote, which is a land-living vertebrate that lays eggs, according to Adam Huttenlocker, an outside specialist on the team who researches early tetrapod fossils and is an assistant professor at USC. Sherry Liang, CNN, 5 Nov. 2021 This new kind of animal, that Dawson would name Hylonomus lyelli, remains the earliest amniote in the fossil record. Hillary Maddin, Smithsonian, 18 July 2019 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'amniote.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin Amniota, from amnion

First Known Use

1878, in the meaning defined above

Time Traveler
The first known use of amniote was in 1878

Dictionary Entries Near amniote

Cite this Entry

“Amniote.” Dictionary, Merriam-Webster, Accessed 21 Feb. 2024.

Last Updated: - Updated example sentences
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