P.S.的全稱是“postscript”
“postscript”這個詞表示“信末簽名后的附筆,又及”,通常的搭配是“postscript to sth”,比如說:
She mentioned in a postscript to her letter that the parcel had arrived.(她在信末附筆中說包裹已寄到。)
其實這個詞是來源于拉丁語“post scriptum”,表示“written after”的意思,也可以說是“that which comes after the writing”的意思。
而postscript的這個縮寫,除了可以寫成“P.S.”外,還可以寫成“PS.”、“PS”或這“p.s.”