The Free On-line Dictionary of Computing (30 December 2018):

packet switching
packet switch
packet-switched

    A communications paradigm in which packets
   (messages or fragments of messages) are individually routed
   between nodes, with no previously established communication
   path.  Packets are routed to their destination through the
   most expedient route (as determined by some routing
   algorithm).  Not all packets travelling between the same two
   hosts, even those from a single message, will necessarily
   follow the same route.

   The destination computer reassembles the packets into their
   appropriate sequence.  Packet switching is used to optimise
   the use of the bandwidth available in a network and to
   minimise the latency.  X.25 is an international standard
   packet switching network.

   Also called connectionless.  Opposite of circuit switched
   or connection-oriented.  See also virtual circuit,
   wormhole routing.

   (1999-03-30)