Pronunciation: (äm"boo-shoor', äm'boo-shoor"; Fr. än-bOO-shyr'),[key] —n., —pl.-churesPronunciation: (-shoorz'; Fr. -shyr').[key] 1. the mouth of a river.
2. the opening out of a valley into a plain.
3. Music. a. the mouthpiece of a wind instrument.
b. the adjustment of a player's mouth to such a mouthpiece.