Refers to a geographical or political area where a country, organization, or person holds dominant influence or control. Often used in geopolitical contexts.
That country is trying to bring its neighbor into its sphere of influence.
冷戦時代、世界は二つの勢力圏に分かれていた。
During the Cold War, the world was divided into two spheres of influence.
That region fell within the neighboring country's sphere of influence.
That great power is trying to expand its sphere of influence in Asia.
The two great powers are competing over spheres of influence.