Point-of-Presence is a location where a Interexchange Carrier (IXC) could terminate services and provide connections into a Local Access and Transport Area (LATA).
Point-of-Presence typically houses servers, routers, network switches, multiplexers, and other network interface equipment.
Point-of-Presence is often located in a Data Center.
ISPs typically have multiple PoPs.
PoPs are often located at Internet exchange points and colocation centres