ps
Synonym discussion
Sense: noun/1
The noun sense of 'P.S.' (or 'ps') refers specifically to a conventional notation placed after a letter's signature. 'Postscript' is the full English word that the abbreviation represents; it sounds more formal and is more common in book footnotes than in personal correspondence. 'Afterthought' describes an idea that occurs to someone later, but it does not carry the specific letter-writing convention and can apply to any delayed thought. 'Addition' is a broad, neutral term that lacks any connection to letters or post-signature placement. For example, you would say 'She added a postscript to the chapter' but 'His remark about the weather was a clear afterthought' — the two are not interchangeable.
Etymology
The abbreviation 'P.S.' comes from the Latin phrase 'post scriptum', meaning 'written after'. The Latin 'post' means 'after' and 'scriptum' means 'something written'. English writers began using the shortened form in letters during the 16th century, and it eventually spread to emails and other digital messages.