You keep using that word. I do not think it means what you think it means.

This is an interesting post for me because I use nerd and geek almost interchangeably. Usually the word I use varies by context - if I'm around a Nerdfighter, I tend to use nerd more frequently, and if I'm around someone who aggressively dislikes one of the words, I'll use the word they prefer (i.e. I have a friend who actively rallies against the label of geek, so I use nerd around him).

I agree with the definition of nerd as someone with varied interests and geek as someone with a passion for one subject, with it being possible to be both; under this definition I'd be a nerd, but also a Doctor Who geek.

The funny thing is, that definition is not how I actually use the words. In everyday usage, I completely swap the nerd definition for the geek one, with it being common for nerd to be used in more language focused or mainstream/more accepted areas (i.e. book nerd, Firefly nerd, politics nerd). I tend to use geek in the situations that, even if accepted now, used to be the hallmark of a social outcast or were deemed weird - for instance a Dungeons and Dragons geek, a model painting geek, or a video game geek.

Did any of that make sense? So I say that a nerd is someone with varied interests who probably is more well-read and pursues intelligence, and a geek is someone with a passion. But what I usually end up meaning is that a nerd has a couple of passions but is more accepted for them, while a geek can have one or many hobbies but they're a little more off-the-wall and might get some weird looks for them.