An idiom meaning a final, authoritative word or pronouncement by someone in power that decides a matter.
会議は紛糾していたが、社長の鶴の一声で結論が出た。
The meeting was in disorder, but the president's authoritative word produced a conclusion.
最終的には監督の鶴の一声でメンバーが決まる。
Ultimately the coach's single authoritative decision determines the members.
予算配分は理事長の鶴の一声で大きく変わった。
The budget allocation changed significantly with the chairman's authoritative pronouncement.