A part of or supplement to a work that is structurally associated with the main body of a cultural work that "contains supplementary information about the body but is not necessariy colocated with it, such as a preface, annotation, afterword, footnote, or glossary."<a href="#cwrc:4c227091-6bf0-4325-b846-9733fae19e61">(Oxford, 2015)</a>