tick

tick n.  1. A {jiffy} (sense 1).  2. In simulations, the
   discrete unit of time that passes between iterations of the
   simulation mechanism.  In AI applications, this amount of time is
   often left unspecified, since the only constraint of interest is
   the ordering of events.  This sort of AI simulation is often
   pejoratively referred to as `tick-tick-tick' simulation,
   especially when the issue of simultaneity of events with long,
   independent chains of causes is {handwave}d.  3. In the FORTH
   language, a single quote character.