拇指孔（保龄球）上供拇指插入的孔

An opening made to fit a thumb, as in a bowling ball.

单簧管，黑管一种管乐器，有直的圆筒形管身和一个外敞的管口及一个单簧吹口，以指孔和键的方式演奏

A woodwind instrument having a straight, cylindrical tube with a flaring bell and a single-reed mouthpiece, played by means of finger holes and keys.