If you're like most civilians, your image will feature a very thin or overweight geek sitting in the semi-dark crouched over a computer with a glazed expression on his pallid face.
He's dressed casually to the point of sloppiness, and has a halo of wild, unwashed hair if he's not wearing a stocking cap.
And you just know that he has as many social skills as a grapefruit.
You have this image of programmers because that's what the media is pushing - they would like you to believe that programmers are a special species who live outside the normal range of human activities, and whom you will never understand.
Interestingly, many programmers accept and even cultivate this image - perhaps in the notion that negative status is better than no status at all.
Like all stereotypes, this image has a grain of truth: I've met a few programmers who fit this image perfectly.
But like all stereotypes, it's not really representative of the programmers that I've worked with over the years.
People tend to throw the term "geek" around as a mildly disparaging word for scientists and engineers who are a little bit short on social skills, but no one seems to know where the term comes from.
Well, it's carny slang.
Most American carnivals have (or had) sideshows that featured "The wild man of Borneo - found in the jungle, raised by gorillas, with inhuman appetites!" The show itself was acted by "the geek," a minor sideshow character, often mentally retarded, who covered himself in filth and dressed in ragged skins.
He howled and threatened the audience and, at the height of the performance, bit the head off a live chicken.
It was shameful, degrading work and "the geek" was a marginalized outcast in the carny community.
So that's where the word "geek" comes from; taken literally it's a pretty insulting, degrading name.
In my experience, engineers and scientists will often refer to themselves or colleagues as "geeks," but can be uncomfortable when civilians use the word without understanding it.
So, in the interest of reducing the stereotype, try to avoid the "g-word" when you can - we'll all be better off for it.