'psittacine' originates from New Latin, specifically the word 'psittacinus', where 'psittacus' meant 'parrot'.

'psittacine' came into scientific English from New Latin 'psittacinus' (itself from Greek 'psittakos' 'parrot') and was adopted into English usage in the 19th century; the compound adjective 'psittacine-related' is a modern descriptive formation based on that root.

Initially it meant 'of or pertaining to parrots', and this basic meaning has remained stable; 'psittacine-related' simply extends that sense to mean 'related to parrots'.