sphere noun
ADJ. wider He wanted to spread his ideas to a wider sphere than the school. | academic, cultural, domestic, economic, military, political, social His work is little known outside the academic sphere. | private, public
PREP. in/within sb's/the ~ The region is within the Russian sphere of influence. | outside sb's/the ~ The matter is outside my sphere of responsibility. | ~ of
PHRASES a sphere of activity/influence/life
You can also check other dicts: sphere (English, 中文解释 ), wordnet sense, Collins Definition