プログレッシブ和英中辞典(第4版)の解説
どうし【同士】
仲間同士じゃないか，口げんかは止せよ
You're pals, aren't you? Now stop that bickering.
兄弟同士のけんか
a quarrel between [among] brothers
気の合った同士でグループを作った
We formed a group of congenial people.
お互いに人間同士だ
We are fellow human beings.
乗客同士がけんかを始めた
The passengers began to quarrel among themselves.
同士打ち
an internal squabble
同士打ちをした
They fought among themselves.
暗闇で同士打ちになった
It was so dark that they (accidentally) attacked those on their own side.