Definition of "appendix"

appendix

/əˈpɛn.dɪks/

noun
plural appendices or appendixes
1. (obsolete in general sense) Something attached to something else; an attachment or accompaniment.
  Quotations
  idleness is an appendix to nobility; they count it a disgrace to work, and spend all their days in sports, recreations, and pastimes […]
  1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps
2. A text added to the end of a book or an article, containing additional information.
3. (anatomy) The vermiform appendix.
4. (anatomy) Any process, prolongation, or projection.