What is the difference between a geek and a nerd?

I had this idiot question somewhere in the back of my mind.

I think those two are somewhat different words.

The Urban Dictionary defines a Geek as:
The people you pick on in high school and wind up working for as an adult.

And the same Dictionary defines Nerd as:
One whose IQ exceeds his weight.

Geek is not to be confused with Nerd. A geek does not have to be smart, a Geek is someone who is generally not athletic, and enjoys Video Games; Comic Books; being on the internet etc.

I wonder if that is true. 😛