What exactly IS skinning?

Ah yes skinning. I have noticed that some of you *cough* Soup *cough* have been wondering *cough* complaining *cough* that you don't know what skinning is. According to my research from http://www.xd.com.au/skinning.xd (Read only first 2 paragraphs, the rest is about a skinning program) , I have found the definition of skinning. Skinning is changing the appearance of something, such as a desktop. Like changing the font, font size, background, ect. *clears throat* My theory is that skinning derives from the original use of skinning, which means to remove the pelt or fur of an animal. When skinning an animal, the animal looks different from when it first started. Also, the animal meat and skin can now be used in many more ways. Being used in different ways, will almost always change the appearance, thus where "online" skinning originated.
Based on this research, it has come to my attention that skinning may not necessarily be a maplestory related item. Sure one may create a maplestory skin, but it does not always have to be maplestory related.

I hope you have enjoyed my concise definition of skinning. Good day