#concept6 mentions

An explanation answers a “why” question.

It refers to a Fact (state of a System) or Event (change in a system) to be explained (the explanandum), and offers an account of why it is the case or has happened (the explanans).

The explanans is a causal, mathematical or conceptual Model of the explanandum that shows how it is

The function of an explanation is to make the explanandum less surprising.