Let’s start with the nerds. These are guys and gals that are really into academics. They’ll probably be deep into a book most of the time, and the few people that actually enjoy their algebra classes. Nerds usually aspire to gain as much knowledge about as many things as they can. As a result of their need for challenge, they will play role playing games or real time strategy games. Their personalities are usually introverted, however they can carry a discussion about their interests for days. Any unwelcomed confrontation with one of these guys will most likely be pretty awkward. Catch them wearing a button up, cargo pants or shorts, some nice shoes, and prescription glasses. And probably packing an inhaler.
Alrighty, now on to the geeks. The geeks are more into a source of entertainment rather than any academic. They will get really into an interest until they know it on an expert level. It could be a video game, TV show, movie franchise, or a comic. Geeks are generally easier to talk to and love talking about their favorite interests. Their sense of style will revolve around whatever they are into. For example, if they like superhero stuff, they might be wearing a superman shirt. If they like 80's stuff, they might be wearing like a Ghostbusters t-shirt or something, you get the point. Other than that, the rest of their style varies from person to person. Some are more hipster-ish with flashy clothes and pointy hair, and others are more subtle with a hoodie and some blue jeans.
So hopefully this article helped separate the two in that noggin of yours. Just make sure that you don’t mix up the two, or you might get beaten with math books or Halo strategy guides by one of your friendly neighborhood nerds/geeks.