<p><strong>Noun</strong></p><ul><li>agreement; concord; harmony: the concordance of the membership.</li><li>an alphabetical index of the principal words of a book, as of the Bible, with a reference to the passage in which each occurs.</li><li>an alphabetical index of subjects or topics.</li><li>(in genetic studies) the degree of similarity in a pair of twins with respect to the presence or absence of a particular disease or trait.</li></ul>