1. device that simulates something: a device, instrument, or piece of equipment designed to reproduce the essential features of something, e.g. as an aid to study or training. See also emulator (sense 2)
2. comput computer program simulating real world: a computer program that simulates something else such as a board game, a vehicle, or a complex system like a city or railway system
3. somebody who simulates something: somebody who feigns or imitates something
