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

• addendum
• afterword
• codicil
• excursus
• supplement

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

Earlier this month, Bindi Irwin had her appendix removed. —Sara Vallone, Miami Herald, 25 May 2025

The appendix can burst within 24 hours or less of symptoms starting. —Brandi Jones, Health, 17 May 2025

That my appendix was being choked by endometriosis. —Cara Lynn Shultz, People.com, 16 May 2025

The otherwise healthy young man who died at Elmhurst Hospital after just over a week on Rikers Island had a ruptured appendix and a lacerated liver — suggesting either medical neglect in the jails or an assault, his family and their lawyer alleged Tuesday. —Graham Rayman, New York Daily News, 18 Mar. 2025

Word History

Etymology

Latin appendic-, appendix, from appendere — see append

First Known Use

1542, in the meaning defined at sense 1a

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