rotor blade vs airfoil

rotor blade and airfoil both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotor blade	Yes	No	No	No
airfoil	Yes	No	No	No

As nouns, airfoil is a hypernym of rotor blade; that is, airfoil is a word with a broader meaning than rotor blade:

rotor blade: the long airfoil that rotates to provide the lift that supports a helicopter in the air
airfoil: a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight

Other hypernyms of rotor blade include aerofoil, control surface, surface.

rotor blade (noun)	airfoil (noun)
the long airfoil that rotates to provide the lift that supports a helicopter in the air	a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight