Added 9 October 2026 appendix /əˈpɛn.dɪks/ noun Categories: LanguageThe BodyEveryday Words Latin root: appendix Wiktionary noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about appendix at Wordnik → Where our words come from → Supplementary material that is collected and appended at the back of a book. A vestigial process that extends from the lower end of the cecum and that resembles a small pouch. Origin Borrowed from Latin appendix. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: add-onsupplementadjunctattachedannexaddendumannexeannexureexhibit Back to today's word