TITLE: In layman's terms: What is a stochastic process?
QUESTION [9 upvotes]: I'm a software engineering student, so I don't have probability theory in my career, but I hear people near my circle talk about stochastic processes very often. Could someone explain in simple words what these are?
E: I'll make myself a bit more precise. I've heard people describe a series of events via a stochastic process, I've read the wiki, and I don't understand how the 'collection of random variables' part comes to play: what does it mean to represent something via a non-deterministic process? 
Could somebody provide a concrete example of a representation of something via a stochastic process (and how it defers from a deterministic process)?

REPLY [3 votes]: I'd like to add that many types of noise are also modeled as stochastic processes. Whenever a person collects data, such a voltage signals, audio signals, or image signals, there will always be small disturbances in the data caused by imperfections in the equipment or the environment. The signal we measure might be given by the formula:
$$measured\ signal = true\ signal + noise $$
One famous example you may have heard of is white noise, which is a stochastic process where the signal value at any given time is completely decorrelated with past and future signal values.