The Free On-line Dictionary of Computing (30 December 2018):
A property of a message passing system in which
each part of a message is transmitted independently and one
part can be forwarded to the next node before the whole
message has been received. All parts of a single message
follow the same route.
The independent parts are normally small, e.g. one 32-bit
word. This reduces the latency and the storage requirements
on each node when compared with message switching where a
node receives the whole message before it starts to forward it
to the next node. It is more complex than message switching
because each node must keep track of the messages currently
flowing through it.
With cut-through switching, wormhole routing is applied to
packets in a packet switching system so that forwarding of
a packet starts as soon as its destination is known, before
the whole packet had arrived.