A collating sequence is a set of rules that define how characters in a character set are ordered. It is used to determine how characters are sorted, searched, and compared. Collating sequences are important for many applications, such as databases, search engines, and text editors.
There are many different collating sequences available, each of which is designed for a specific language or region. For example, the English collating sequence orders characters alphabetically, while the Chinese collating sequence orders characters by their radical and stroke count.