Source : Free On-Line Dictionary of Computing

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)