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 handwaved. 3. In the FORTH
language, a single quote character.