The most common and most likely answer to this crossword clue is the 6 letter word ARENAS
I've seen this crossword clue in The Daily Telegraph
A
R
E
N
A
S
More clues leading to the result ARENAS
- America’s more rational to retreat in stages
- Bowls and fields around mid-morning?
- Answer before more sensible revolutionary rings
- In more sensible area, set up venues for big events
- East of Libya, more rational to retreat in battlegrounds
- In regions, start to need stadia
- Bowls and fields around end of green
- Player in parts of game settings
- Endless arsenal built on fields
- Sports venues write up more reasonable article
Buddy explains!

The straight part
We know that "battlegrounds" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case battlegrounds = arenas.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ARENAS mean?
ARENAS noun- An enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (North America) or circular area for bullfights (especially Hispanic America).
- The building housing such an area; specifically, a very large, often round building, often topped with a dome, designated for indoor sporting or other major events, such as concerts.
- The sand-covered centre of an amphitheatre where contests were held in Ancient Rome.
- A realm in which events take place; an area of interest, study, behaviour, etc.