Noun
1. (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"2. 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)
3. representation of something (sometimes on a smaller scale)
4. the act of giving a false appearance;
"his conformity was only pretending"