a part that goes over or into the mouth of a person;
"the mouthpiece of a respirator"
an acoustic device; the part of a telephone into which a person speaks
a spokesperson (as a lawyer)
(especially boxing) equipment that protects an athlete's mouth
the tube of a pipe or cigarette holder that a smoker holds in the mouth
the aperture of a wind instrument into which the player blows directly
- He put his hand over the mouthpiece and called his wife to the phone.
- They would breathe it as a powder into their lungs, through a mouthpiece device.
- The newspaper was only a mouthpiece of certain rich people.
Putting your hand over the mouthpiece often doesn't work with modern phones.出自：Which?