mouthpiece vs sports equipment

mouthpiece and sports equipment both are nouns.

Word	Noun	Adjective	Verb	Adverb
mouthpiece	Yes	No	No	No
sports equipment	Yes	No	No	No

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

mouthpiece (noun)	sports equipment (noun)
the aperture of a wind instrument into which the player blows directly	equipment needed to participate in a particular sport
the tube of a pipe or cigarette holder that a smoker holds in the mouth
an acoustic device; the part of a telephone into which a person speaks
(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)