addendum

1. 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.
2. A postscript.
3. 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.

الجمع addenda