Definition of "Simulation" :

noun: the act of giving a false appearance

noun: 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)

noun: representation of something (sometimes on a smaller scale)

noun: (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."