Definitions of mouthpiece:

  • noun:   the aperture of a wind instrument into which the player blows directly
  • noun:   the tube of a pipe or cigarette holder that a smoker holds in the mouth
  • noun:   an acoustic device; the part of a telephone into which a person speaks
  • noun:   (especially boxing) equipment that protects an athlete's mouth
  • noun:   a part that goes over or into the mouth of a person
    Example: "The mouthpiece of a respirator"
  • noun:   a spokesperson (as a lawyer)