 Chaos has been invoked as an explanation for, or as contributing substantially to explanations of, actual-world behaviors. Some examples are epileptic seizures, heart fibrillation, neural processes, chemical reactions, weather, industrial control processes and even forms of message encryption. Aside from irregular behavior of actual-world systems, chaos is also invoked to explain features such as the actual trajectories exhibited in a given state space or the sojourn times of trajectories in particular regions of state space. But what, exactly, is the role chaos plays in these various explanations? More succinctly, what are chaos explanations? 