battlefield vs battleground

battlefield and battleground both are nouns.

Word	Noun	Adjective	Verb	Adverb
battlefield	Yes	No	No	No
battleground	Yes	No	No	No

As nouns, battlefield and battleground are synonyms defined as:

battlefield and battleground: a region where a battle is being (or has been) fought

Other synonyms of battlefield include field, field of battle, field of honor.

battlefield (noun)	battleground (noun)
a region where a battle is being (or has been) fought	a region where a battle is being (or has been) fought