What is the use of the white balance setting for dslr camera?

I'm confuse what is the use of the color to be set in dslr when choosing the white balance. For example i'm selecting the cloudy then i press the o then it will let you choose different colors. Can you explain to me the use og that color? Please help me. I'm just and beginner in this hobby. I'm using an nikon d60 dslr.

I guess there's no point in typing a half-baked five sentence explanation if comprehensive articles are freely available on the internet:
http://www.cambridgeincolour.com/...alance.htm