This is a good comment from Thomas Eicher, about defining cyberpunk:

"Gibson said it in a short story somewhere. Cyberpunk is the stuff that has EDGE written all over it. You know, not edge, it's written EDGE. All capital letters. Now ask me how I'd define EDGE. Well, EDGE is not about definitions. To the contrary, things so well known that they provide an exact definition can't be EDGE. They probably once were but now they ain't. SO DON'T TRY TO DEFINE IT!!!"

Cyberpunk really is The Undefinable. One cannot give it an exact meaning. Cyberpunk is personal. Anyway, there's some meaning, and yes, really many meanings, for cyberpunk, what it is, and what it should be. Here is the definition used on this site. Read the disclaimer first.

Definition of Cyberpunk

These papers try to throw some light on what cyberpunk is about, and they will ground our definition.

Cyber + Punk = Cyberpunk

Describes the history and literal meaning of the word 'cyberpunk'.

Section Cyberpunk

Gives dictionary and FAQ definitions for cyberpunk.

Cyberpunk Understood

A letter from The Cyberpunk Project, by Christian Kirtchev.

Cyberpunk - Aspects and Expectations

An essay by Janne Järvinen.

Time Has Come Today

A modern days explanation.

According to these, we can consider that cyberpunk has two sides, like a coin has: [1] On the one hand it's a literary/science fiction genre, [2] on the other hand it's a living subculture and a social movement originally based on the cyberpunk science fiction.

More about these two sides of cyberpunk, and also some other aspects derived from them:

[1] Cyberpunk as a Science Fiction Genre

Read what alt.cyberpunk FAQ says about this.

Continue to "Cyberpunk as a Science Fiction Genre" page, where we try to define cyberpunk literary style and point you to the real artwork.

[2] Cyberpunk as a Subculture

Read what alt.cyberpunk FAQ says about this.

Continue to "Cyberpunk as a Subculture" page, which tells about fundamental aspects of Cyberpunk the Subculture, or, "The Movement".

Cyberpunk, the Social Theory?

Cyberpunk can also be considered as a social and political theory, which tries to explain and understand our present-day society through cyberpunk science fiction. Like always, science fiction is not only about future, it's also about the present, and this applies particularly to cyberpunk.

Cyberpunk is often associated especially with postmodern discourse about our world of rapid cultural changes from industrial to post-industrial society - changes towards information society.

More about this in "Cyberpunk as a Social Theory".

Mainstream Cyberpunk

Cyberpunk is also a pop culture phenomenon based on [1] and [2], but we exclude it here as a wannabee fuss. No one really calls themself a cyberpunk in that meaning anymore, because it sounds stupid and invites people to spit on you because you are a trendy out-of-it loser.

More about this mainstream cyberpunk phenomenon and about cyberpunk in public media:

The Confusion Over Cyberpunk

What the media associates with cyberpunk does not agree with the commonly accepted interpretation of the movement.
By Daniel Shih.

Mainstreaming Cyberpunk

Short cyberpunk history and definitions, and how cyberpunk was mainstreamed by billy idols, from book Escape Velocity - Cyberculture at the End of the Century by Mark Dery.

Other Comments on What Cyberpunk Is

Other definitions for cyberpunk by magazines, cyberpunk authors and fellow cyberpunks.