mouthpiece vs aperture

mouthpiece and aperture both are nouns.

Word	Noun	Adjective	Verb	Adverb
mouthpiece	Yes	No	No	No
aperture	Yes	No	No	No

As nouns, aperture is a hypernym of mouthpiece; that is, aperture is a word with a broader meaning than mouthpiece:

mouthpiece: the aperture of a wind instrument into which the player blows directly
aperture: an man-made opening; usually small

As nouns, aperture is a hypernym of mouthpiece; that is, aperture is a word with a broader meaning than mouthpiece:

mouthpiece (noun)	aperture (noun)
the aperture of a wind instrument into which the player blows directly	an man-made opening; usually small
the tube of a pipe or cigarette holder that a smoker holds in the mouth	a device that controls amount of light admitted
an acoustic device; the part of a telephone into which a person speaks	a natural opening in something
(especially boxing) equipment that protects an athlete's mouth
a part that goes over or into the mouth of a person
a spokesperson (as a lawyer)