MOUTHPIECE

Mouth″piece′ (?), n. 1. 1. The part of a musical or other instrument to which the mouth is applied in using it; as, the mouthpiece of a bugle, or of a tobacco pipe.
2. 2. An appendage to an inlet or outlet opening of a pipe or vessel, to direct or facilitate the inflow or outflow of a fluid.
3. 3. One who delivers the opinion of others or of another; a spokesman; as, the mouthpiece of his party.
Egmont was imprudent enough to make himself the mouthpiece of their remonstrance. Motley.