An index (plural: indexes) is a list of words or phrases ('headings') and associated pointers ('locators') to where useful material relating to that heading can be found in a document. In a traditional back-of-the-book index the headings will include names of people, places and events, and concepts selected by a person as being relevant and of interest to a possible reader of the book. The pointers are typically page numbers, paragraph numbers or section numbers. In a library catalog the words are authors, titles, subject headings, etc., and the pointers are call numbers.
- I certainly think that the best book in the world would owe the most to a good index, and the worst book, if it had but a single good thought in it, might be kept alive by it.
- Horace Binney, To S. Austin Allibone; reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 974.
- So essential did I consider an index to be to every book, that I proposed to bring a bill into Parliament to deprive an author who publishes a book without an index of the privilege of copyright, and, moreover, to subject him for his offense to a pecuniary penalty.
- John Campbell, 1st Baron Campbell, Lives of the Chief Justices of England (1874), Preface to Volume III.
- An index is a necessary implement. * * * Without this, a large author is but a labyrinth without a clue to direct the readers within.
- Thomas Fuller, Worthies of England (1662).
- The index tells us the contents of stories and directs to the particular chapters.
- How index-learning turns no student pale, Yet holds the eel of science by the tail.
- That roars so loud and thunders in the index.
- And in such indexes, although small pricks
To their subsequent volumes, there is seen
The baby figure of the giant mass
Of things to come at large.