A concordance is an alphabetical list of the principal words used in a book or body of work, with their immediate contexts. Because of the time and difficulty and expense involved in creating a concordance in the pre-computer era, only works of special importance, such as the Bible, Qur'an or the works of Shakespeare, had concordances prepared for them. Even with the use of computers, producing a concordance (whether on paper or in a computer) may require much manual work, because they often include additional material, including commentary on, or definitions of, the indexed words, and topical cross-indexing that is not yet possible with computer-generated and computerised concordances.

However, when the text of a work is on a computer, a search function can carry out the basic task of a concordance, and is in some respects even more versatile than one on paper. A bilingual concordance is a concordance based on aligned parallel text. A topical concordance is a list of subjects that a book (usually The Bible) covers, with the immediate context of the coverage of those subjects. Unlike a traditional concordance, the indexed word does not have to appear in the verse. The most well known topical concordance is Nave's Topical Bible.