A: Index is a Chinese word pronounced su ǒ y ǐ n, which means a tool for searching books and materials.

Extension:

explain

According to certain needs, extract the main contents or titles of books and periodicals, indicate the source and page number, and arrange them in a certain order for people to consult. Also called "attraction". ?

source

Song Ceng Gong's "Moving to Cangzhou and Going to the Temple": "The country that floats on the finger is not weighed, but it is lost, and it is not as good as it is." This refers to brushed fibers.

Baidu encyclopedia-index