looking glass是梳妆镜的意思,through就是穿过.
在《爱丽丝漫游仙境记》中,爱丽丝就是穿过梳妆镜前往童话世界的；
Alice in Wonderland and Through the Looking Glass 的通用译名是：
爱丽丝漫游奇境记与镜中世界,或简称“爱丽丝漫游仙境记”；
He's through the looking glass.这并不是一个符合语法规范的句子,因为through是介词,原句应为：He's going through the looking glass.他正在穿过梳妆镜.