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

According to the Mayo Clinic, appendicitis is an inflammation of the appendix that often results in a patient needing to have their appendix surgically removed. —Charlotte Phillipp, People.com, 11 May 2025

On Saturday, her brother Robert Irwin revealed that Bindi underwent immediate surgery due to a ruptured appendix. —Christina Dugan Ramirez, FOXNews.com, 11 May 2025

Katie Thurston Says Her Breast Cancer Diagnosis Has Changed After Second Opinion: ‘No Chemo’ for Now Although Butlin’s appendix had been removed during surgery, the disease had already spread to her pelvis and lymph nodes. —Vanessa Etienne, People.com, 14 Apr. 2025

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