addendum

noun

addition made to a document following its publication

L316033 on Wikidata ↗

Wiktionary

Pronunciation: /əˈdɛn.dəm/ / /əˈden.dəm/

noun

Etymology: From the gerundive of Latin addere (“to add”).

Something to be added; especially text added as an appendix or supplement to a document.
“An addendum was added to the contract to clarify payment terms.”
“The author included an addendum at the end of the book.”
A postscript.
The height by which the tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line.