[noun] - abbreviation for postscript. It is written at the end of a letter after it has been signed to introduce extra text....Yours sincerely, R. Langdale. P.S. Give my best wishes to your father.A PS is a postscript.Don't rewrite the letter - just add a PS.
PS
Meaning of PS in English
Cambridge English vocab. Кембриджский английский словарь. 2012