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

collision detection

    A class of methods for sharing a data
   transmission medium in which hosts transmit as soon as they
   have data to send and then check to see whether their
   transmission has suffered a collision with another host's.

   If a collision is detected then the data must be resent.  The
   resending algorithm should try to minimise the chance that two
   hosts's data will repeatedly collide.  For example, the
   CSMA/CD protocol used on Ethernet specifies that they
   should then wait for a random time before re-transmitting.

   See also backoff.

   This contrasts with slotted protocols and token passing.

   (1997-03-18)