budgerigar vs parrakeet

budgerigar and parrakeet both are nouns.

Word	Noun	Adjective	Verb	Adverb
budgerigar	Yes	No	No	No
parrakeet	Yes	No	No	No

As nouns, parrakeet is a hypernym of budgerigar; that is, parrakeet is a word with a broader meaning than budgerigar:

budgerigar: small Australian parakeet usually light green with black and yellow markings in the wild but bred in many colors
parrakeet: any of numerous small slender long-tailed parrots

Other hypernyms of budgerigar include parakeet, paraquet, paroquet, parroket, parroquet.

budgerigar (noun)	parrakeet (noun)
small Australian parakeet usually light green with black and yellow markings in the wild but bred in many colors	any of numerous small slender long-tailed parrots