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

Common treatments for this type of cancer include surgery to remove the appendix and any other affected organs, as well as chemotherapy to kill any metastasized cancer cells. —Melissa Rudy, FOXNews.com, 10 June 2025

The five-year survival rate for low-grade appendix tumors is between 67 to 97 percent. —Tom Gavin, EverydayHealth.com, 10 June 2025

The appendix is a small pouch that hangs off the large intestine on the lower right side of the abdomen. —Linda Carroll, NBC news, 9 June 2025

The appendix does not perform any essential bodily tasks. —Brandi Jones, Health, 17 May 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