Battlefield, Battleground
noun
A war location is the battlefield. That's where the wars are fought, anyways.
せんじょう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
すみません。今、戦場にいるので電話に出られないんです。
Sorry. I can't pick up the phone right now because I'm on the battlefield.
今日のオフィスはヤクザの戦場のようだった。
The office today was like a yakuza battlefield.
コウイチは頼れるやつだ。たとえ戦場にいたとしても、俺達を決して見捨てやしないよ。
Koichi is a dependable guy. He would never let us down even if we were on a battlefield.