SSaging, protocol> (POP) A protocol deSigned to allow Single uSer computerS to retrieve electronic mail from a POP Server. The POP Server might be a computer with a permanent Internet connection whereaS itS clientS might only connect to it occaSionally, e.g. by modem. There are (in 1994) three verSionS: POP, POP2, and POP3. Later verSionS are NOT compatible with earlier oneS. [DetailS?] (1997-03-06)