PS, or postscript, is used to denote a sentence, idea, or paragraph appended after the main body of a letter or text. It comes from the Latin postscriptum which translates to “written after”. According to Dictionary.com, the word came into English from the early 1500s.
The dictionary states as one definition that postscript is, “a paragraph, phrase, etc., added to a letter that has already been concluded and signed by the writer.” However, in electronic communication, such as email, the PS is sometimes placed before the writer’s signature. Yet, in every case, it is added after the main body and expresses supplementary information.