An index is a reference book that arranges the items with retrieval significance in the literature in an orderly way. These items can be names, places, words, concepts or other items for retrieval. It is a retrieval tool for finding words, concepts, articles or other contents in books, periodicals or other documents. It usually consists of a series of items arranged alphabetically or in other logical order. Its basic function is to reveal the content of literature and guide readers to find literature.

Development history

Formerly known as general inspection, preparation inspection or introduction. The basic unit of composition is the index item. Entries generally include index words, explanations or notes, and sources. All index items are arranged in order. Its essential feature is that it only reveals the source of content or literature clues, and does not directly provide facts and materials themselves.

Its main function is to provide clues for people to obtain documents accurately and quickly. Common indexes mainly include newspaper index, anthology index, word index, sentence index, keyword index, proper name index, subject index and so on.