ARPANET is short for "Advanced Research Projects Agency Network".

It was the first computer network to feature packet switching. This is the same technology which went on to build the Internet. ARPANET can be viewed as fore runner to the Internet, and comrpised an early part of it. ARPANET was jointly created by MIT and DARPA in the US. The network was funded by the U.S. government in 1960's. UCLA and the Stanford Research were the first two nodes that formed the ARPANET. At this stage the Internet's first computers were at academic and government institutions and were mainly used for accessing files and to send email.