附言,又及(全写为postscript,用于信末) something written at the end of a letter to introduce some more information or sth that you have forgotten. PS is an abbreviation for postscript .
PS Could you send me your fax number again? 又及:请再把您的传真号码发给我好吗?
She added a PS asking me to water the plants. 她加了一句附言,要我浇花。