whirlybird vs skyhook

whirlybird and skyhook both are nouns.

Word	Noun	Adjective	Verb	Adverb
whirlybird	Yes	No	No	No
skyhook	Yes	No	No	No

As nouns, skyhook is a hyponym of whirlybird; that is, skyhook is a word with a more specific, narrower meaning than whirlybird:

whirlybird: an aircraft without wings that obtains its lift from the rotation of overhead blades
skyhook: helicopter carrying a reel of steel cable that can be used to lift and transport heavy objects

Other hyponyms of whirlybird include cargo helicopter, shuttle helicopter, single-rotor helicopter.

whirlybird (noun)	skyhook (noun)
an aircraft without wings that obtains its lift from the rotation of overhead blades	a hook that is imagined to be suspended from the sky
	helicopter carrying a reel of steel cable that can be used to lift and transport heavy objects