Definition of Term: Stochastic

A simulator is referred to as stochastic if running it more than once with a given input configuration will produce randomly different output(s).

Example: A simulator of a hospital admissions system has as inputs a description of the system in terms of number of beds, average time spent in a bed, demand for beds, etc. Its primary output is the number of days in a month in which the hospital is full (all beds occupied). The simulator generates random numbers of patients requiring admission each day, and random lengths of stay for each patient. As a result, the output is random. Running the simulator again with the same inputs (number of beds, etc) will produce different random numbers of patients needing admission and different random lengths of stay, and so the output will also be random.