em·bou·chure 
(äm′b-shr)
(äm′b-shr)n.
1. The mouth of a river.
2. Music
a. The mouthpiece of a woodwind or brass instrument.
b. The manner in which the lips and tongue are applied to such a mouthpiece.
[French, from emboucher, to put or go into the mouth, from Old French : en-, in; see EN-1 + bouche, mouth (from Latin bucca, cheek).]