Definition of: appendix

(ə·pen′diks) noun plural ·dix·es or ·di·ces (-də·sēz)
1. An addition or appendage, as of supplementary matter at the end of a book.
2. An appendage.
3. Anat. a The vermiform appendix, b A process or projection; an outgrowth or prolongation.
4. Aeron. A large tube hanging from a spherical balloon, through which the gas passes in or out. [<L, an appendage <appendere. See APPEND.] Synonyms: addendum, addition, supplement. We add an appendix to a book, as a dictionary, to contain names, dates, lists, etc., which would encumber the text; we add a supplement to supply omissions, as, for instance, to bring it up to date. An addition might be matter interwoven in the body of the work, an index, plates, editorial notes, etc., which might be valuable additions, but are not within the meaning of appendix or supplement. See APPENDAGE.