What does Zimen mean? What's the explanation?

Take the word as the door. If you enter through this door, you can understand the principles of all dharma, so it is called the word door. Each word has its own meaning attached to it. There are 42-zi gates, 5-zi gates, 8-zi gates, 19-zi gates, 26-zi gates, and 5-zi gates. (1) The forty-two-character door is revealed by the Four Mindfulness Chapters of Volume 5 of the Great Prajna Sutra, Volume 57 of the Old Avatamsaka Sutra, etc., namely: A, Luo, Bo, Zha, Na, Luo, Tuo, Po, Tu, Sha, He, Duo, Ye, Zha, Jia, Suo, Mo, Jia, He, Jia, [Qi*pi], Tuo, Credit, Xie, Cha, Duo, Ruo, [Wu*zhai], Po, Che, Mo, Huo, Shou, Ga, Ta, Na, Po, Ge, Li, Zhe, Zha, Tu. These forty-two-character gates are not arranged in the order of the five-cross gates, but adopt a unique arrangement, including more than ten non-alphabetic characters (ligatures).