arena
/əˈriːnə/noun
1- a level area surrounded by seating, in which sports, entertainments, and other public events are held（四周设有座位以供竞技、娱乐以及其他公共事件使用的）场地。
1.1
- a place or scene of activity, debate, or conflict活动场所; 辩论场所; 冲突场所：
he has re-entered the political arena.
他重新踏上政治舞台。
词源
early 17th cent.: from Latin harena, arena 'sand， sand-strewn place of combat'.