Appendix (8)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">appendix</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for addendum that I've seen before include "Dud ad-men dealt with in end of book" , "Item appended to book" , "something tacked on" , "Extra item added at end of book" , "Extra piece of text" .)
(Other definitions for addenda that I've seen before include "Items added to a text" , "appendages" , "Postscripts, supplements" , "collection of extra material" , "Printed appendices" .)