POP – Point of presence
Point of Presence is an access point of an ISP or any large organization to the outside world we call “Internet”. A large organization or ISP may have multiple POPs, with each POP consists of an array of networking devices. These devices may include: a router, ATM switches, frame relays, digital/analog call aggregators etc.
A typical POP should have one or more unique IP addresses and a pool of assignable IP addresses for its clients. An ISP’s POP provide internet connectivity to its clients in a substantially large area.
Also see: POP full form in Computer (email)