Stochastic is a term used to describe a process that is RANDOM and unpredictable. It is derived from the Greek word 'stochastikos' which means 'aiming at a target'. Stochastic processes are used in many fields, including mathematics, physics, economics, and computer science. In mathematics, stochastic processes are used to model phenomena that exhibit randomness or uncertainty. In physics, stochastic processes are used to describe the behavior of particles in a system. In economics, stochastic processes are used to model the behavior of markets and other economic systems. In computer science, stochastic processes are used to generate RANDOM numbers and simulate complex systems.