Short for Network Access Point, a public network exchange facility where Internet Service Providers (ISPs) can connect with one another in peering arrangements.
The NAPs are a key component of the Internet backbone because the connections within them determine how traffic is routed. They are also the points of most Internet congestion.
For more information:
How the Internet Runs! How the networks of world interconnect to become the Intenet. A free, lecture-based presentation on how the networks of the World interconnect to create the Internet. Covers NAP, PNAP, Internet History, Internet organizations and protocols.
IC Network Systems. Home page for ICS Network Systems, an Internet services provider that runs North America's Big East NAP (Network Access Point).