a ‧ re ‧ na /əˈriːnə/ BrE AmE noun [countable]
[ Date: 1600-1700 ; Language: Latin ; Origin: 'sand, sandy place' ]
1 . a building with a large flat central area surrounded by seats, where sports or entertainments take place:
a sports arena
an indoor arena
2 . the political/international/public etc arena all the activities and people connected with politics, public life etc:
Women are entering the political arena in larger numbers.
American economic activity in the international arena