bat ‧ tle ‧ field /ˈbætlfiːld/ BrE AmE ( also bat‧tle‧ground /bætlɡraʊnd/) noun [countable]
1 . a place where a battle is being fought or has been fought
2 . a subject that people disagree or argue a lot about:
Education has become a political battleground.
3 . a place where an argument or disagreement happens, or where people are competing against each other:
a battleground state during the election