What is the content of Ci Hai and what is its use to us?

To put it bluntly, as the name implies, bid farewell to the sea. Just like the ocean of words, it contains almost all the words you know but don't know, and explains them one by one. We can think of her as an ultra-luxurious dictionary and an encyclopedia, but it covers all kinds of fields. It can be said that if you can read Ci Hai through, you will certainly benefit a lot. It is ok to look up unfamiliar words or unfamiliar names and places when studying, but it seems that no one will study them. After all, it is a reference book. If you love reading or studying, it is recommended to put one on the bookcase, even if it is a collection. In addition, it supports a variety of word search methods. There is a lot of knowledge in the appendix, but it is a bit too big for students to carry. I wonder if this answer is satisfactory?