noun (plural appendices /-diˌsēz/; appendixes)
- 1 Anatomy a tube-shaped sac attached to and opening into the lower end of the large intestine in humans and some other mammals. Also called vermiform appendix.
In humans the appendix is small and has no known function, but in rabbits, hares, and some other herbivores it is involved in the digestion of cellulose
Appendix typically has the plural appendixes in the anatomical sense, and appendices when referring to a part of a book or document.