ar·​cho·​saur ˈär-kə-ˌsȯr How to pronounce archosaur (audio)
: any of a subclass (Archosauria) of reptiles comprising the dinosaurs, pterosaurs, and crocodilians
archosaurian adjective or noun

Examples of archosaur in a Sentence

Recent Examples on the Web Newsletter Sign up for our email newsletter for the latest science news Scientists have unveiled a new species of archosaur, a reptile that existed around the dawn of the dinosaurs. Joshua Rapp Learn, Discover Magazine, 15 Aug. 2023 That's because the initial dig was focused more on ancient mammal fossils, so these archosaur fossils gathered academic dust for a time. Joshua Rapp Learn, Discover Magazine, 15 Aug. 2023 They were also accompanied by archosaurs, a group that included early dinosaurs. Sean Mowbray, Discover Magazine, 21 June 2023 At the end of the Triassic period, small-sized dinosaurs roamed Earth alongside other groups of archosaurs—that is, until a widespread extinction event cleared the way for dinos to put on some serious size. Darren Orf, Popular Mechanics, 16 May 2023 The new analysis of the two Chinese pterosaurs’ pycnofibers, however, could be seen as evidence for another hypothesis: that the currently unknown archosaur ancestor of both dinosaurs and pterosaurs had feathers of some type, and passed the trait down to both groups. Gemma Tarlach, Discover Magazine, 17 Dec. 2018 Finding evidence of warm-bloodedness in all major groups of dinosaur suggests that endothermy was an ancestral trait that evolved earlier in the archosaur lineage. Gemma Tarlach, Discover Magazine, 14 Feb. 2020 Finding Antarctanax is particularly significant not only for Antarctic paleontology but for understanding archosaur evolution in general. Gemma Tarlach, Discover Magazine, 31 Jan. 2019 But they were related, as part of the same larger archosaur family tree that today includes crocodiles and the surviving dinosaurs, birds. Gemma Tarlach, Discover Magazine, 13 Mar. 2018 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'archosaur.' 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 Archosauria, from Greek archōn + sauros lizard

First Known Use

1933, in the meaning defined above

Time Traveler
The first known use of archosaur was in 1933

Dictionary Entries Near archosaur

Cite this Entry

“Archosaur.” Dictionary, Merriam-Webster, Accessed 2 Dec. 2023.

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