Stochastic

Stochastic (from the Greek στόχος for aim or guess) means random. A stochastic process is one whose behavior is non-deterministic, in that a system's subsequent state is determined both by the process's predictable actions and by a random element. However, according to M. Kac^[1] and E. Nelson^[2], any kind of time development (be it deterministic or essentially probabilistic) which is analyzable in terms of probability deserves the name of stochastic 
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Foot notes

#1 http://en.wikipedia.org/wiki/Stochastic