The Collaborative International Dictionary of English v.0.48:

Simulation \Sim`u*la"tion\, n. [F. simulation, L. simulatio.]
   The act of simulating, or assuming an appearance which is
   feigned, or not true; -- distinguished from dissimulation,
   which disguises or conceals what is true.
   [1913 Webster]

   Syn: Counterfeiting; feint; pretense.
        [1913 Webster]

WordNet (r) 3.0 (2006):

simulation
    n 1: the act of imitating the behavior of some situation or some
         process by means of something suitably analogous
         (especially for the purpose of study or personnel training)
    2: (computer science) the technique of representing the real
       world by a computer program; "a simulation should imitate the
       internal processes and not merely the results of the thing
       being simulated" [syn: simulation, computer simulation]
    3: representation of something (sometimes on a smaller scale)
       [syn: model, simulation]
    4: the act of giving a false appearance; "his conformity was
       only pretending" [syn: pretense, pretence, pretending,
       simulation, feigning]

The Free On-line Dictionary of Computing (19 January 2023):

simulation
simulate

    Attempting to predict aspects of the
   behaviour of some system by creating an approximate (mathematical)
   model of it.  This can be done by physical modelling, by writing a
   special-purpose computer program or using a more general
   simulation package, probably still aimed at a particular kind of
   simulation (e.g. structural engineering, fluid flow).  Typical
   examples are aircraft flight simlators or electronic circuit
   simulators.

   A great many simulation languages exist, e.g. Simula.

   See also emulation, Markov chain.

   (1995-02-23)