A concordance is an alphabetical list of the principal words used in a book or body of work, listing every instance of each word with its immediate context. Only works of special importance have had concordances prepared for them, such as the Vedas,[1] Bible, Qur'an or the works of Shakespeare or classical Latin and Greek authors,[2] because of the time, difficulty, and expense involved in creating a concordance in the pre-computer era.
A concordance is more than an index; additional material make producing them a labor-intensive process, even when assisted by computers, such as commentary, definitions, and topical cross-indexing.
In the precomputing era, search technology was unavailable, and a concordance offered readers of long works such as the Bible something comparable to search results for every word that they would have been likely to search for. Today, the ability to combine the result of queries concerning multiple terms (such as searching for words near other words) has reduced interest in concordance publishing. In addition, mathematical techniques such as Latent Semantic Indexing have been proposed as a means of automatically identifying linguistic information based on word context.