プログレッシブ和英中辞典(第３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. - 同士打ちをした
They fought among themselves. - 暗やみで同士打ちになった
It was so dark that they (accidentally) attacked those on their own side.