Try Our Apps


Avoid these words. Seriously.


[in-deks] /ˈɪn dɛks/
noun, plural indexes, indices
[in-duh-seez] /ˈɪn dəˌsiz/ (Show IPA)
(in a nonfiction book, monograph, etc.) a more or less detailed alphabetical listing of names, places, and topics along with the numbers of the pages on which they are mentioned or discussed, usually included in or constituting the back matter.
a sequential arrangement of material, especially in alphabetical or numerical order.
something used or serving to point out; a sign, token, or indication:
a true index of his character.
something that directs attention to some fact, condition, etc.; a guiding principle.
a pointer or indicator in a scientific instrument.
a piece of wood, metal, or the like, serving as a pointer or indicator.
  1. a value that identifies and is used to locate a particular element within a data array or table.
  2. a reference table that contains the keys or references needed to address data items.
Also called fist, hand. Printing. a sign in the shape of a hand with extended index finger, used to point out a particular note, paragraph, etc.
a light, smooth cardboard stock.
the forefinger.
a number or formula expressing some property, ratio, etc., of something indicated:
index of growth; index of intelligence.
Statistics. index number.
Economics. price index.
  1. an exponent.
  2. the integer n in a radical defining the n- th root: ∛ is a radical having index three.
  3. a subscript or superscript indicating the position of an object in a series of similar objects, as the subscripts 1, 2, and 3 in the series x 1 , x 2 , x 3 .
  4. winding number.
Horology. a leverlike regulator for a hairspring.
(initial capital letter) Roman Catholic Church.
  1. Index Librorum Prohibitorum.
  2. Index Expurgatorius.
(usually initial capital letter) any list of forbidden or otherwise restricted material deemed morally or politically harmful by authorities:
an Index of disapproved books relating to Communism.
  1. a table of contents.
  2. a preface or prologue.
verb (used with object)
to provide with an index, as a book.
to enter in an index, as a name or topic.
to serve to indicate:
warm breezes indexing the approach of spring.
to place (a book) on an official list as politically or morally harmful:
The commissar insisted on indexing the book.
to rotate (work) on a milling machine in order to repeat the milling operation at a new position.
Economics. to adjust (wages, taxes, etc.) automatically according to changes in the cost-of-living level or another economic indicator, especially to offset inflation.
Origin of index
1350-1400; Middle English < Latin: informer, pointer, equivalent to in- in-2 + -dec- (combining form of dic-, show, declare, indicate; akin to teach) + -s nominative singular ending
Related forms
indexable, adjective
indexer, noun
indexical, adjective
indexically, adverb
indexless, adjective
nonindexed, adjective
overindex, verb (used with object)
overindexing, noun
reindex, verb (used with object)
unindexed, adjective
well-indexed, adjective
Can be confused
appendix, index, supplement (see synonym study at appendix) Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
Cite This Source
Examples from the Web for indexed
Contemporary Examples
Historical Examples
  • From a drawer of his desk the Admiral drew out an indexed book.

  • They lay with others neatly typed and indexed in Heldon Foyle's office.

    The Grell Mystery Frank Froest
  • Arranged, bound, indexed, all these at once become accessible and valuable.

    Medical Essays Oliver Wendell Holmes, Sr.
  • You have seen scores of such books and know how they are indexed and priced.

    Paul and the Printing Press Sara Ware Bassett
  • It has been labelled and indexed and filed away in the archives of the profession.

    The Blind Spot Austin Hall
British Dictionary definitions for indexed


noun (pl) -dexes, -dices (-dɪˌsiːz)
an alphabetical list of persons, places, subjects, etc, mentioned in the text of a printed work, usually at the back, and indicating where in the work they are referred to
(library science) a systematic list of book titles or author's names, giving cross-references and the location of each book; catalogue
an indication, sign, or token
a pointer, needle, or other indicator, as on an instrument
  1. another name for exponent (sense 4)
  2. a number or variable placed as a superscript to the left of a radical sign indicating by its value the root to be extracted, as in ³√8 = 2
  3. a subscript or superscript to the right of a variable to express a set of variables, as in using xi for x1, x2, x3, etc
a numerical scale by means of which variables, such as levels of the cost of living, can be compared with each other or with some base number
a number or ratio indicating a specific characteristic, property, etc: refractive index
Also called fist. a printer's mark (☛) used to indicate notes, paragraphs, etc
(obsolete) a table of contents or preface
verb (transitive)
to put an index in (a book)
to enter (a word, item, etc) in an index
to point out; indicate
to index-link
to move (a machine or a workpiece held in a machine tool) so that one particular operation will be repeated at certain defined intervals
Derived Forms
indexer, noun
indexless, adjective
Word Origin
C16: from Latin: pointer, hence forefinger, title, index, from indicāre to disclose, show; see indicate
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for indexed



"compile an index," 1720, from index (n.). Related: Indexed; indexing.



late 14c., "the forefinger," from Latin index (genitive indicis) "forefinger, pointer, sign, list," literally "anything which points out," from indicare "point out" (see indication). Meaning "list of a book's contents" is first attested 1570s, from Latin phrases such as Index Nominum "Index of Names," index expurgatorius "specification of passages to be deleted from works otherwise permitted." Scientific sense (refractive index, etc.) is from 1829; economic sense (cost-of-living index, etc.) is from 1870, from the scientific usage, from sense "an indicator." The Church sense of "forbidden books" is from index librorum prohibitorum, first published 1564 by authority of Pius IV.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
indexed in Medicine

index in·dex (ĭn'děks')
n. pl. in·dex·es or in·di·ces (-dĭ-sēz')

  1. A guide, standard, indicator, symbol, or number indicating the relation of one part or thing to another in respect to size, capacity, or function.

  2. A core or mold used to record or maintain the relative position of a tooth or teeth to one another or to a cast.

  3. A guide, usually made of plaster, used to reposition teeth, casts, or parts.

  4. The index finger.

in'dex' v.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
indexed in Culture

index definition

An alphabetical list of subjects treated in a book. It usually appears at the end of the book and identifies page numbers on which information about each subject appears.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source

Word of the Day

Nearby words for indexed

Difficulty index for index

All English speakers likely know this word

Word Value for indexed

Scrabble Words With Friends