Awhile ago i wrote about the distinction between geek and nerd: a nerd is a guy who is passionate about a subject and he is working in that field already, while a geek is only a fan of that subject.
In the video from above you can see that the origins of the word “geek” go way back into the 30s, where geek would mean a freak, a guy who works in a circus and does a ton of stunts. Later on geek meant an anti-social guy and now geeks are popular guys who are fans of science, IT and so on.
Nerd, or knurd, on the other hand was a term coined in 1950, in the Book “I ran the zoo”, from Dr. Seuss, referring to what would be put in a zoo. Nerd or nert, a word which may have originated from nuts as in “nerts”, meant stupid or crazy person.
A nerd is more like an academia guy nowadays, whereas a geek is someone who enjoys and is a fan of a given work field. Both are seen as passionate about their domain of interest, however geeks are more poplar and nerds are more an anti-social type.
Now you know what a geek is and what a nerd is. Now go geek out or nerd out about something that you like.