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

• 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

Their analysis, which includes seven figures, thirteen tables, six appendices, and nearly 25,000 words, revealed three main findings. —Ge Bai, Forbes.com, 28 Aug. 2025

In a heartfelt Instagram post, the conservationist revealed the removal of 51 endometriosis lesions, a chocolate cyst, her appendix, and repair of a hernia from childbirth. —Khloe Quill, FOXNews.com, 17 Aug. 2025

Nobody’s taking my appendix out here. —Lizz Schumer, People.com, 13 Aug. 2025

Roth missed a month this summer after having his appendix taken out. —John Maffei, San Diego Union-Tribune, 24 July 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