datagram

n. package of data, package of information containing the origin and destination addresses which is transferred on a network (Computers)

For uses of the word "Packet" outside Information Technology, see Packet In information technology, a packet is a formatted block of data carried by a packet mode computer network. Computer communications links that do not support packets, such as traditional point-to-point telecommunications links, simply transmit data as a series of bytes,  characters, or bits alone. When data is formatted into a packet, the network can transmit long messages more efficiently and reliably.
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In packet switching, a self-contained packet, independent of other packets, that contains information sufficient for routing from the originating data terminal equipment (DTE) to the destination DTE without relying on prior exchanges between the equipment and the network. Note: Unlike virtual call service, when datagrams are sent there are no call establishment or clearing procedures. Thus, the network may not be able to provide protection against loss, duplication, or misdelivery.

A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network.
See also connectionless, frame, packet.

datagram