Where does “post-postscript” come from?

post-postscript (English) comes from English post, from Middle French poste, from Italian posta, from Latin probāre, from Latin probō, from Latin Probus, from Proto-Indo-European pro-bhwo-, from Proto-Indo-European pro- — passed , crossed.

post-postscript (English): An addendum added after a postscript

Definitions

  1. An addendum added after a postscript

Ancestry of “post-postscript”, step by step

post-postscript traces back through two separate lines of ancestry.

via English post

StepLanguageWordMeaning
1EnglishpostA long dowel or plank protruding from the ground;...
2Middle Frenchposte
3Italianpostamail, post; post office; stakes
4Latinprobāre
5Latinprobōto approve, permit, commend
6LatinProbusgood, serviceable, excellent, superior, able
7Proto-Indo-Europeanpro-bhwo-being in front, prominent
8Proto-Indo-Europeanpro-toward, forward
9Proto-Indo-Europeanpor-to give birth; forward, through; going, passage
10Proto-Indo-Europeanper-before, in front; first; to go through
11Proto-Indo-Europeanpr̥tóspassed , crossed

via English postscript

StepLanguageWordMeaning
1EnglishpostscriptAn addendum to a letter, added after the author's...
2New Latinpostscriptumaccusative supine of postscrībō
3Latinpostscriptuswritten after
4LatinpostscriboI write after or under
5Latinscrībōto write
6Proto-Italicskreiβōto carve
7Proto-Indo-Europeanskreybʰ-to write
Every word from Proto-Indo-European pr̥tós