shell parakeet vs parrakeet

shell parakeet and parrakeet both are nouns.

Word	Noun	Adjective	Verb	Adverb
shell parakeet	Yes	No	No	No
parrakeet	Yes	No	No	No

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

shell parakeet: 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 shell parakeet include parakeet, paraquet, paroquet, parroket, parroquet.

shell parakeet (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