budgerigar UK /ˈbʌd͡ʒəɹiˌɡɑː/US /ˈbʌd͡ʒəɹiˌɡɑɹ/ noun1 •A species of small green parakeet, Melopsittacus undulatus, native to inland Australia; a common cagebird throughout the world and bred in many colour varieties. formsbudgerigars