Source : Webster's Revised Unabridged Dictionary (1913)

Appendix \Ap*pen"dix\, n.
   The vermiform appendix.

Appendix \Ap*pen"dix\, n.; pl. E. {Appendixes}, L. {Appendices}.
   [L. appendix, -dicis, fr. appendere. See {Append}.]
   1. Something appended or added; an appendage, adjunct, or
      concomitant.

            Normandy became an appendix to England. --Sir M.
                                                  Hale.

   2. Any literary matter added to a book, but not necessarily
      essential to its completeness, and thus distinguished from
      supplement, which is intended to supply deficiencies and
      correct inaccuracies.

   Syn: See {Supplement}.

Source : WordNet®

appendix
     n 1: supplementary material that is collected and appended at the
          back of a book
     2: a vestigial process that extends from the lower end of the
        cecum and that resembles a small pouch [syn: {vermiform
        appendix}, {vermiform process}, {cecal appendage}]
     [also: {appendices} (pl)]