postscript
n. countablen. a short note at the end of a letter or email that you add after you have already finished writing. It is usually for something you forgot to mention.
n. a brief note or message added to the end of a letter or document after the main body has been completed. Often used to provide additional information or a polite closing.
I forgot to mention my phone number in the letter, so I added a postscript.
The author included a postscript in the final chapter to address some of the questions readers had about the ending.
While the main body of the report focused on fiscal policy, the postscript provided a brief history of the committee's formation and its initial objectives.
From New Latin postscriptum, from Latin, neuter of postscriptus, past participle of postscrībō (“write after”), from post (“after”) + scrībō (“write”). By surface analysis, post- + script.