appendix

noun

ap·​pen·​dix ə-ˈpen-diks 

plural appendixes or appendices ə-ˈpen-də-ˌsēz 

1

a

: appendage

b

: supplementary material usually attached at the end of a piece of writing

The book's appendix includes a bibliography.

2

: a bodily outgrowth or process

specifically : vermiform appendix

Synonyms of appendix

• epilogue
• supplement
• documentation
• afterword
• addition
• addendum
• codicil
• conclusion

Examples of appendix in a Sentence

In your textbooks, turn to Appendix 3: Glossary of Terms.

The book has several appendixes.

Recent Examples on the Web

The employment agreement includes an appendix that releases the university from all claims for incidents or events prior to the contract’s effective date. — Daniel Libit, Sportico.com, 27 June 2026

An upcoming public health assessment will address the study in an appendix, agency spokesperson Nancy Nydam Shirek said in an email to the AJC. — Kristi Swartz, AJC.com, 26 June 2026

There was a stage four tumor in the appendix. — Cara Lynn Shultz, PEOPLE, 15 June 2026

Orlando’s worldwide image as a suburban appendix to theme parks was eclipsed by its status as a beacon of tolerance and love. — Orlando Sentinel Editorial Board, The Orlando Sentinel, 11 June 2026

Word History

Etymology

borrowed from Latin appendic-, appendix "something subordinate or supplementary attached to a larger unit," fr. appendere, presumably "to attach to something larger by hanging " + -ic-, -ix, noun suffix — more at append

Note: Regarding the meaning of appendere see note at append.

First Known Use

1549, in the meaning defined at sense 1b

Phrases Containing appendix

• vermiform appendix

Kids Definition

appendix

noun

ap·​pen·​dix ə-ˈpen-diks 

plural appendixes or appendices -də-ˌsēz 

1

: additional material attached at the end of a piece of writing

2

: a small tube that is closed at one end and projects from the pouch marking the beginning of the large intestine in the lower right side of the abdomen

Medical Definition

appendix

noun

ap·​pen·​dix ə-ˈpen-diks 

plural appendixes or appendices -də-ˌsēz 

: a bodily outgrowth or process

specifically : vermiform appendix