This is the 7030th most frequent Korean word.
전투에
"In battle" or "to battle."
The word "전투에" here indicates the act of going into or getting involved in combat or battle.
그는 전투에 참가하기 위해 준비하고 있다.
He is preparing to participate in the battle.
In this sentence, "전투에" connects the noun battle with the action of donating items for its cause.
그 여사가 전투에 의복과 물자를 기부했다.
The lady donated clothing and supplies to the battle.
Here, "전투에" signifies the situation or position of being in an active combat or confrontation.