What is a corpus?

Baidu Encyclopedia also has an explanation, but I guess you have seen it.

I'll explain it in my own words according to my own understanding, hoping to help you ~

Corpus is to put together language materials that have really appeared in real life, such as sentences we usually speak, sentence paragraphs in some literary works, sentence paragraphs that have appeared in newspapers and magazines, etc., to form a corpus, so that we can draw materials from it or get data to prove it when doing scientific research.

For example, I want to write an article about the popularity of the word "Geili", and I can look up the frequency, usage and so on in the corpus.