Nerd are people who concerned with mainly things seen as 'uncool' by the general populace. Being extraordinarily tech-savvy, skilled at video games or role-playing games, very well informed in the maths or sciences, are some of the main characteristics. They are 'the smart ones.'
But those of you familiar with the theory of multiple intelligence should know that while nerds may be smart in some regions, their defining feature is being socially 'stupid.' They cannot interact well with anyone, often not with other nerds. This does not make them bad people, nor good. It just means they are not interpersonally intelligent. In some cases, interpersonal intelligence is more useful than technical, so shut up about being proud of nerdiness!
If you are socially inept, it does not mean you are a nerd. Likewise, you can be intelligent and like uncool things but it does not mean you are a nerd. Any definition that says nerds can have social lives and lots of friends and can be popular- they are wrong. Those are not nerds. Those are smart people who are obviously socially intelligent. A nerd requires BOTH aspects of 'uncool' interests AND a lack of interactive skills.

One whose IQ exceeds his weight.

An individual persecuted for his superior skills or intellect, most often by people who fear and envy him.

An 'individual', i.e. a person who does not conform to society's beliefs that all people should follow trends and do what their peers do. Often highly intelligent but socially rejected because of their obesssion with a given subject, usually computers. Unfortunately, nerds seem to have problems breeding, to the detriment of mankind as a whole.

A stereotypical label used to describe a person that is socially inadequate. A four letter word, but a six figure income.

A person who gains pleasure from amassing large quantities of knowledge about subjects often too detailed or complicated for most other people to be bothered with.

Often mistaken for Geeks, who aspire to become nerds, yet lack the intelligence, and end up giving nerds a bad name due to their poor social skills.

Non-nerds are often scared of nerds, due to their detailed knowledge, and therefore seemingly high levels of intelligence - and subsequently denegrate them as much as possible as often as possible.

Nerds exist covertly within the fabric of society, often choosing to 'nerd it up' in private or in the company of fellow nerds. It is for this reason they are feared the most - unlike geeks, who are easily identified, nerds can only be found out when casual conversation reaches a subject that they like nerding.

Never
Ending
Radical
Dude.

the group of people who will most likely make a life changing invention that will radically change the world. the computer was invented by a nerd. the macintosh/apple and windows were invetned by nerds. jocks and normal people have no claim to civilization except for being the hard labor. nerds actually do the thinking. so jocks, fuck you, and go eat your steroids