Archosauria, the archosaur clade, is a crown group that includes the most recent common ancestor of living birds and crocodilians.
From the en.wikipedia.org
Archosauria is normally defined as a crown group, which means that it only includes descendants of the last common ancestors of its living representatives.
From the en.wikipedia.org
Archosauria is within the larger clade Archosauriformes, which includes some closely related relatives of archosaurs such as proterochampsids and euparkeriids.
From the en.wikipedia.org
More examples
A large subclass of diapsid reptiles including: crocodiles; alligators; dinosaurs; pterosaurs; plesiosaurs; ichthyosaurs; thecodonts
(archosaurian) of or relating to reptiles of the subclass Archosauria
Archosaurs (Greek for 'ruling lizards') are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct dinosaurs, many extinct crocodilian relatives, and pterosaurs (although their inclusion has been disputed). ...
A group of animals that includes alligators, dinosaurs and birds.
Clade of diapsids, characterized by a minimum of the following traits: openings anterior to the orbits (antorbital fenestrae), teeth with serrations compressed laterally and none on the palate, dentary fenestrae, differently shaped calcaneum, and elongated ilium and pubis. ...