比喻在关键时刻一下子做出决定或解决问题to have the final say; to set the tune with a single beat of the gong

• 他评茶精密细致,凡审评有争议的,都由他一锤定音"

  He is meticulous and precise in assessing tea, and whenever there are disputes in the assessment, he always has the final say.

• 7月20日,我省的阶梯电价方案一锤定音。

  On the 20th of July, the final say was had on the stepped electricity price proposal for this province.