appendix

in anatomy
https://doi.org/10.1351/goldbook.10422
  1. Tube-shaped sac ("vermiform appendix") attached to and opening into the upper end of the large intestine (cecum) in humans and some other mammals.
  2. Appendage, blind sac, or diverticulum.
See also: epididymal appendix
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 726 (https://doi.org/10.1515/pac-2015-1202)