What did ARPANET originally stand for?

ARPANET originally stood for Advanced Research Projects Agency Network.

The name referred to the network created by the U.S. Department of Defense’s Advanced Research Projects Agency, or ARPA. ARPA funded the project to let researchers at universities and laboratories share expensive computing resources and communicate across long distances.

ARPANET was built as a packet-switched network. Instead of reserving one continuous communications path, it divided messages into packets that could travel through the network and be reassembled at their destination. This design helped inspire the more general Internet architecture.

The name is sometimes expanded incorrectly as “Advanced Research Program Agency Network,” but “Projects” is the official word. ARPANET should also not be confused with the World Wide Web: ARPANET was an early network infrastructure, while the Web was later created by Tim Berners-Lee as a system for linking and accessing information through browsers.

The first ARPANET connection was established in 1969, and the network was formally decommissioned in 1990.