Bird-footed dinosaur and Saurischian dinosaur

Bird-footed dinosaur noun - Any of numerous carnivorous dinosaurs of the Triassic to Cretaceous with short forelimbs that walked or ran on strong hind legs.

Saurischian dinosaur and bird-footed dinosaur are semantically related. In some cases you can use "Saurischian dinosaur" instead a noun phrase "Bird-footed dinosaur".

Saurischian dinosaur noun - Herbivorous or carnivorous dinosaur having a three-pronged pelvis like that of a crocodile.

Bird-footed dinosaur and saurischian dinosaur are semantically related. Sometimes you can replace phrase "Bird-footed dinosaur" with "Saurischian dinosaur", this phrases are similar.