archosaur

noun

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
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The discovery immediately sparked debate over the evolutionary pathways of miniaturization and morphological convergence, challenging assumptions about how small archosaurs could become and how to interpret highly specialized skull forms in the fossil record. Scott Travers, Forbes.com, 29 Apr. 2025 During the Triassic, a broad group known as the archosaurs evolved and eventually split into two major lineages. Sean Mowbray, Discover Magazine, 1 Aug. 2024 Nesbitt says that these small differences are what paleontologists expected to find, especially as researchers find fossils that sit closer to the common ancestor of all archosaurs. Joshua Rapp Learn, Discover Magazine, 15 Aug. 2023 Birds and crocodilians are archosaurs, the living relatives of non-avian dinosaurs and pterosaurs. Jeanne Timmons, Ars Technica, 26 July 2023 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

Word History

Etymology

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

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Cite this Entry

“Archosaur.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/archosaur. Accessed 25 May. 2025.

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