(1) (Point of Presence) The point at which a line from a long distance carrier (IXC) connects to the line of the local telephone company or to the user if the local company is not involved. For dial-up access to the Internet via analog modem, the POP is the local telephone exchange that the modem dials into to log in. See Super POP.

(2) (Post Office Protocol) See POP3.

(3) Retrieve an item from a stack. See push/pop.

(4) (Package for Online Programming) See POP-1.