A nerd is a single-minded enthusiast. A computer nerd is a single-minded computer enthusiast.
I might get downvoted for this, but most of the time "nerd" also implies social awkwardness and uncoolness, and not getting laid a lot.
What I'm trying to say is, I don't like being called a nerd. Let's stop acting like we don't know it's unpleasant to call/be called a nerd.
Those used to be the connotations with the word 'nerd', but they really aren't anymore. Being a 'nerd' is cool these days, and nerd has become a term of endearment.
the reply was snarky because the definitions are essentially circular