written matter following the main text of a book

MATTER at the end of a book, usually containing ENDNOTES, the INDEX, and the BIBLIOGRAPHY, etc.

Any material that follows the main body of text--for example, bibliography, glossary, reference tables and charts, and indexes. (cf. body, front matter)

Supplementary information that comes after the main text in a printed book. Within the context of software documentation, it typically includes appendices, the and glossary. See also front matter.