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

The findings of his investigation, however, appear as an appendix in Kay’s habeas corpus appeal. —Sam Blum, New York Times, 14 Apr. 2025

An appendix covers animals including giant and swarm variations. —Rob Wieland, Forbes, 20 Feb. 2025

No one plans on having their appendix burst or having a heart attack. —Dené K. Dryden, Twin Cities, 20 Feb. 2025

Despite his success, the demands of Avicii’s career took a toll on his well-being: The hitmaker had a series of health problems over the years, including a bout with acute pancreatitis and surgery to have his gallbladder and appendix removed. —Lynsey Eidell, People.com, 31 Dec. 2024

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