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Syllabification: ar·cho·saur
Pronunciation: /ˈärkəˌsôr
(also archosaurus /ˌärkəˈsôrəs/)

Definition of archosaur in English:


Zoology & Paleontology
A reptile of a large group that includes the dinosaurs and pterosaurs, represented today only by the crocodilians.
Example sentences
  • Other archosaurs included the pterosaurs, relatives of dinosaurs but not true dinosaurs.
  • At the same time, the broad, dry plains of equatorial Pangea provided a proving ground for a strange new group of lightweight, but large-bodied, archosaurs - the dinosaurs.
  • The archosaur skull includes two new fenestra (skull openings).


1930s: from modern Latin Archosauria, from Greek arkhos 'chief' or arkhōn 'ruler' + -saur.



Pronunciation: /ˌärkəˈsôrēən/
Example sentences
  • The hot dry Pangean deserts of the Triassic would witness the competition between the synapsid proto-mammals that had dominated the land uptil now, and the newly emerged archosaurian reptiles (thecodonts).
  • It is interesting that as the archosaurian reptiles were becoming larger, the cynodonts became smaller, perhaps nocturnal.
  • The first vertebrates to evolve true flight were the pterosaurs, flying archosaurian reptiles.

Definition of archosaur in:

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a narrow valley, especially in Scotland or Ireland