| PSI | coextensive with the order Psittaciformes |
|---|---|
| PSI | an order of birds including parrots and amazons and cockatoos and lorikeets and lories and macaws and parakeets |
| PSI | primitive dinosaur actually lacking horns and having only the beginning of a frill |
| PSI | primitive dinosaur actually lacking horns and having only the beginning of a frill |
| PSI | an atypical pneumonia caused by a rickettsia microorganism and transmitted to humans from infected birds |
| PSI | infectious disease of birds |
| PSI | a genus of Psittacidae |
| PSI | African parakeet |
| PSI | type genus of the Psittacidae: usually restricted to the African gray |
| PSI | commonly domesticated gray parrot with red-and-black tail and white face |