(CNN) -- Do you know the difference between a nerd and a geek?

Maybe you think you do. But it turns out the semantics of these social concepts are deeply personal -- especially for people who identify as "nerd" or "geek".

Over the last year, CNN's Geek Out! asked many celebrities what they think the difference is. Their answers illustrated how we use the words "nerd" and "geek" to refer to a certain kind of person, but almost no one agrees on a specific definition.

Around the same time these interviews began, a Venn diagram was popping up on blogs all over the internet. It showed three overlapping circles that plotted the combinations of intelligence, social ineptitude and obsession that form a nerd, a geek, a dork or a dweeb.

And while many self-professed nerds and geeks really appreciated the chart's mathematically-based approach to categorizing their identities, the chart also started some heated debate about delineations.

Ben Nugent, author of "American Nerd: The story of My People," calls himself a "nerd," but by his own definition, he could be considered a "geek" about "nerds."

"'I geek out' on something means 'I know a lot about it,' it's an area of expertise. [Geek] means someone who is almost excessively expert in a particular subject," Nugent said. In other words, "geeking out" is the act of becoming a "know-it-all."

He points out that the words "nerd" and "geek" have very different etymologies, even though now they can almost be used interchangeably.

"Nerd," Nugent said, was first printed in the 1950 Dr. Seuss book, "If I ran the zoo." One of the creatures in the zoo -- an angry looking old man -- is called a nerd, but bears little resemblance to what people generally think of as a nerd today.

Later, Nugent said, in 1951, a Newsweek article referred to the word "nerd" as regional Detroit, Michigan slang for a "drip or a square." For the next three decades, "nerd" did not have many positive associations, he said.

The word "geek" started out meaning almost the exact opposite of the word "nerd."

"It was used in the early 20th century as a term for a carnie who was so unskilled at doing tricks or entertaining people that the only thing he could do at the carnival to get an audience was to bite the heads off of live animals. What it denoted was a real loser who was really unskilled," Nugent said.

And while images of nerds from "Saturday Night Live" sketches and movies like 1984's "The Revenge of the Nerds" showed weak but intelligent characteristics, the word "geek" was applied to inventors from Silicon Valley who had money, power and expertise.

"And so ["geek" has] come to mean something more like an empowered nerd. A nerd who is defined by his knowledge of a certain subject," Nugent said.

There are many people who prefer to be called a "geek" because of that empowerment factor.

Mike Krahulik and Jerry Holkins, the creators of the Web comic "Penny Arcade" and founders of the PAX convention are solidly in the "geek" camp.

" I think being a geek is cool... A geek has an ownership of their geek nature," said Holkins. "[Nerds] don't. It's my hope that nerds become geeks via a natural process. That they learn that their inherent nature isn't something they need to feel ashamed of. I feel like 'nerd' is the epithet, and 'geek' is the inside term."

Others, like David X. Cohen, co-creator of "Futurama," prefer to be called a nerd.

"To me, nerd is a compliment and geek is an insult," said Cohen. "I feel like with 'nerd culture,' [it sounds like] the nerds have triumphed. 'Geek' has a negative connotation. I'd rather be called a nerd. I love being called a nerd."

His "Futurama" coworkers, voice actors Phil LaMarr, John DiMaggio and Billy West think "nerd" is a synonym for "cool." They might be biased; there are at least four writers with Ph.D.s on the "Futurama" staff.

"'Nerd' is an intellectual designation. 'Geek' is a social designation. You can be both and you can be one and not the other. "'Bubblegum' Tate" is a nerd but not a geek," LaMarr said.

DiMaggio and West agree that the character "'Bubblegum' Tate" -- a mathematical genius and a Harlem Globetrotter -- is one of the coolest characters on "Futurama." LaMarr points out that the things that interest "Bubblegum Tate" are nerdy.

"Like if you're into math and you're into comic books, detailed stuff -- that's nerdy. Geeky is not about your mental state, it's how you relate to the world. If you can't look a pretty girl in the face, that doesn't mean you're smart. Like, you could be that and dumb. Then you're not a nerd, you're just a geek," he said.

Most celebrities Geek Out! spoke to claim they are a combination of both nerd and geek.

Musical satirist and pop culture icon 'Weird' Al Yankovic said he thinks of himself as a nerd in general, but is a geek about a few things.

"To me, a nerd is somebody that would be intelligent perhaps to the point of being a bit socially awkward and a geek is somebody that is not necessarily intelligent, usually they are, but they are usually savant-like experts in a particular subject. I know the standard definition of a geek is a person that bites the heads off birds, but I don't think that's been in use for quite some time. But there are certainly nerds that are geeks and geeks that are nerds. There are also pure geeks and pure nerds," Yankovic said.

Brendon Small, an animator who created "Home Movies," and "Metalocalypse," and who now tours as a guitarist with the Metalocalypse band said, "The ultimate trick that musicians played on the world was that they're cool. They're not cool, they're all nerds. They all love "Monty Python," "Star Wars" and "RUSH." Everybody from Cannibal Corpse to Metallica, they are all nerds. We are all nerds."

But, he said, they didn't always call themselves "nerds."

"No one called them nerds back in the '80s and mid-'90s. No one were geeks or nerds, they were just interested in things. It just means you're very, very interested in things and you have a lot of knowledge about it."

Kunal Nayyar, who plays "Raj Koothrappali" on the CBS show "The Big Bang Theory," said he relates to the geek culture portrayed in the show.

"I know what it feels like to be passionate about something," he said. "And these guys are very passionate about their lifestyle. They're very passionate about comic books, they're very passionate about what they wear, they're very passionate about their work."

"So the term 'geek' or 'nerd,' it really just transcends to someone who's very passionate about a certain lifestyle. You see a lot of people living their lives in the middle. These guys don't. They don't live their life in the middle, they go for whatever they want. And of course, according to the regular society it's really not the norm, but I think we share that similarity: I'm very passionate about my craft and my acting, and these guys are very passionate about astrophysics," Nayyar said.