To me, the word composition simply means that every aspect of the image works together. The impact of the individual pieces of the image(be they objects, light or shadow, or even an apparent abscence) , presented and positioned to create more than the sum of themselves.

To me an image has good composition if everything "Fits", or "Compliments each other".

That said, I still have alot to learn about it. 

But I think I'm on the path to learning....