/ ˌsɪmjuˈleɪʃn; NAmE / noun
1.
[ C , U ] a situation in which a particular set of conditions is created artificially in order to study or experience sth that could exist in reality :
a computer simulation of how the planet functions
a simulation model
2.
[ U ] the act of pretending that sth is real when it is not :
the simulation of genuine concern