Explanation

I had heard several times the four different kinds of explanations defined by Aristotle. While listening to Think again course, I decided to finally write the list down, as I usually tend to forget them:

1. Causal: citing the event that brought about (or sustained) the thing to be explained
• Why did the bridge collapse? 
• The earthquack shook it.
2. Teleological: giving the purpose or function of the phenomenon that it explains
• Why did Joe go to the grocery shop?
• To buy milk.
3. Formal: citing the shape or the form of the thing to be explained
• Why doesn't this peg fit in that round hole?
• The pig is square.
4. Material: citing the material that makes up the thing to be explained
• Why is this golf club light?
• It is made of graphite. 

How could one define the meaning of "explanation" itself?

Explanation is an attempt to fit a particular phenomenon into a general pattern in order to increase understanding why the phenomenon happened and remove bewilderment or surprise. Explanation is not persuasion or justification or generalization or prediction.