Slang dictionary
Rule 34
or r34
What does Rule 34 mean?
Content warning: The following article contains explicit references to sexual language, which are included because they document the real-world use of this term.
Rule 34 means “If it exists, there is porn of it. No exceptions.” This is an imaginary law that states that if there’s any conceivable idea that could be turned into pornography, then that type porn already exists. This refers specifically to the immense ubiquity of porn materials across the internet, which cover a wide range of subjects that are considered socially unacceptable or just plain bizarre.
Where does Rule 34 come from?

In 2004, British teenager Peter Morley-Souter posted an internet comic on the website Zoom-Out, which depicts a character shocked to discover Calvin and Hobbes porn on the internet. The comic is then captioned “Rule #34: There is porn of it. No exceptions.”
This comic went viral, and like many strange things on the internet, found its way to the 4chan message boards. It was incorporated as one of 4chan’s Rules of the Internet, and in 2008 it spawned an enormous thread of sexually explicit images meant specifically to prove that Rule 34 is correct, by depicting a myriad of odd and outlandish sexual scenes with inanimate objects, fruits, cartoon characters, giant robots, tetris blocks, gummy bears, and, by definition, anything else you could possibly imagine.
However, a study by Harvard computational neuroscientist Ogi Ogas has shown some evidence that Rule 34 isn’t quite what it used to be. While all of the obscure niche porn still exists, it’s become harder to find due to changes in the pornography websites and how they make money. None of that prevents billions of weird porn images from lurking in every corner of the internet, of course, but it means that users need to look a little harder for them.
Examples of Rule 34
Who uses Rule 34?
Rule 34 has become a common reference when a person encounters pornography that they believe to be unusual, extreme, and/or disturbing. Strange sexual cartoons would be included, or non-sexual images that appear to depict genitalia (such a carrot that resembles a penis), are often cited as examples of Rule 34.
Rule 34 has also become an adult drinking game, which involves friends getting together, coming up with a bizarre idea for porn, and then searching for it until someone finds an example—once again, proving the accuracy of this lovely rule.
The concept of Rule 34 inspired a science fiction novel also titled Rule 34, by Charles Stross, which went on to be nominated for the Arthur C. Clarke Award and the Locus Award in 2012.
Note
This is not meant to be a formal definition of Rule 34 like most terms we define on Dictionary.com, but is rather an informal word summary that hopefully touches upon the key aspects of the meaning and usage of Rule 34 that will help our users expand their word mastery.