Originally this was a term for the unpredictable part of a network that data travels through on its way to its final destination. In a packet-switched network, the physical path on which the data packet travels can vary from one packet to the next. In a circuit-switched network, the specific circuit can vary from one connection to the next.
It later morphed into "the cloud" - which refers to a style of computing in which dynamic, scalable and virtual resources are provided over the Internet. Known as cloud computing, it refers to services that provide common business applications online, which are accessed from a Web browser, while the software and data are stored on the servers.