When there are several appendices, what is that part of a book called?

Question

If a book has one appendix, it is The Appendix. Now consider a book with three appendices (or, if you like, appendixes), named Appendix A, Appendix B, and Appendix C. The part of the book, which is formed by these, is called

• still The Appendix, because it is that part of the book, composed of the "chapters" Appendix A, Appendix B, and Appendix C.
• now The Appendices (or, if you like, The appendixes), because there are three of them and that calls for a plural.
• something else (what)?

Answer 1

Really, there's no standard except whatever the publishers, authors, and editors agree on. I've seen both singular and plural deployed in this way, in different books.

You could call it the Back Matter, which avoids the Singularity, putting it in a class with the Index, Colophon, Cast of Characters, Diagrams, etc.

Answer 2

As an example, Dorland's Illustrated Medical Dictionary (2,000+ pages) has a section at the back labeled "Appendices" with a table of contents listing all of the following appendices. Then each appendix is labeled on its respective page "Appendix 1" through "Appendix 18."

I would call this section of the book the Appendices. (That's also what Dorland's calls it in the table of contents at the front of the book.)