mouthpiece
1. [ noun ] a part that goes over or into the mouth of a person
Examples:

"the mouthpiece of a respirator"

Related terms: aperture respirator
2. [ noun ] an acoustic device; the part of a telephone into which a person speaks
Related terms: acoustic_device telephone
3. [ noun ] (especially boxing) equipment that protects an athlete's mouth
Synonyms: gumshield
Related terms: sports_equipment boxing
4. [ noun ] the tube of a pipe or cigarette holder that a smoker holds in the mouth
Related terms: tube pipe cigarette_holder
5. [ noun ] (informal) a spokesperson (as a lawyer)
Synonyms: mouth
Related terms: spokesperson colloquialism
6. [ noun ] (music) the aperture of a wind instrument into which the player blows directly
Synonyms: embouchure
Related terms: aperture wind_instrument