helicopter vs skyhook

helicopter and skyhook both are nouns.

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

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

helicopter: 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 helicopter include cargo helicopter, shuttle helicopter, single-rotor helicopter.

helicopter (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