互相伤害用英语可以说作 "mutual harm" 或 "mutual injury"。这两个词都指两个人或多个人之间相互伤害。例如，两个人互相攻击或互相欺负，都可以称作 "mutual harm" 或 "mutual injury"。

例句：

They were always fighting and causing mutual harm to each other. 他们总是互相打架，对彼此造成互相伤害。

Mutual harm can be caused by lack of communication and understanding. 缺乏沟通和理解可能会造成互相伤害。

这两个词都来源于拉丁语。"Mutual" 源自拉丁语 "mutualis"，意为 "reciprocal" 或 "shared"。"Harm" 和 "injury" 都源自拉丁语 "injuria"，意为 "injury" 或 "wrong"。