/ ˈpəʊstskrɪpt; NAmE ˈpoʊst-/ noun postscript (to sth)
1.
( abbr. PS ) an extra message that you add at the end of a letter after your signature
2.
extra facts or information about a story, an event, etc. that is added after it has finished
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WORD ORIGIN
mid 16th cent.: from Latin postscriptum , neuter past participle (used as a noun) of postscribere write under, add, from post after, later + scribere write.