packet

In computing, unit of data sent across a network. As well as the actual substance of the message, every packet carries error-control information and details of its origin and its final target, enabling a router to send it on to the intended recipient. This means that packets belonging to the same file can travel via different routes over the network, to be automatically reassembled in the correct sequence when they arrive at their destination. All traffic on the Internet consists of packets. See also TCP/IP and X.25.