rotor coil vs armature

rotor coil and armature both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotor coil	Yes	No	No	No
armature	Yes	No	No	No

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

rotor coil: the rotating armature of a motor or generator
armature: coil in which voltage is induced by motion through a magnetic field

rotor coil (noun)	armature (noun)
the rotating armature of a motor or generator	coil in which voltage is induced by motion through a magnetic field