Discrete Event Simulation (DES) models the operation of a system as a (discrete) sequence of events in time. Each event occurs at a particular instant in time and it marks a change in the state. It is assumed that there is no change in the system between consecutive events. It is commonly used to simulate real life events or systems.
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Sourabh Nandi on 2nd Jan 2021.