quad vs extensor

quad and extensor both are nouns.

Word	Noun	Adjective	Verb	Adverb
quad	Yes	No	No	No
extensor	Yes	No	No	No

As nouns, extensor is a hypernym of quad; that is, extensor is a word with a broader meaning than quad:

quad: a muscle of the thigh that extends the leg
extensor: a skeletal muscle whose contraction extends or stretches a body part

Other hypernyms of quad include extensor muscle.

quad (noun)	extensor (noun)
a rectangular area surrounded on all sides by buildings	a skeletal muscle whose contraction extends or stretches a body part
(printing) a block of type without a raised letter; used for spacing between words or sentences
a muscle of the thigh that extends the leg
one of four children born at the same time from the same pregnancy