a region where a battle is being (or has been) fought
"they made a tour of Civil War battlefields"
The area where a land battle is or was fought, which is not necessarily a field.
"The ruins of the ancient city served as the battlefield where thousands fell during the siege."
In plain English: A battlefield is any place where two opposing forces fight against each other, usually involving soldiers and weapons.
"The soldiers returned home from the battlefield with stories of their hard fight."
Usage: Use battlefield to refer specifically to the location of combat rather than any open space used for sports or recreation. Remember that while it often implies an actual grassy field, the term applies equally to urban streets or forests where fighting occurred.
The word battlefield is a straightforward compound formed from the words battle and field. It has always referred to an open space where fighting takes place.