(1) Also referred to as a network cloud. In telecommunications, a cloud refers to a public or semi-public space on transmission lines (such as T1 or T3) that exists between the end points of a transmission. Data that is transmitted across a WAN enters the network from one end point using a standard protocol suite such as Frame Relay and then enters the network cloud where it shares space with other data transmissions. The data emerges from the cloud -- where it may be encapsulated, translated and transported in myriad ways -- in the same format as when it entered the cloud. A network cloud exists because when data is transmitted across a packet-switched network in a packet, no two packets will necessarily follow the same physical path. The unpredictable area that the data enters before it is received is the cloud.
(2) See also cloud computing.