Its actually pr0n, and its spelled this way so that it doesn't show up when someone searches the word "porn".

It was introduced as a masking tool to prevent people from logging your involvement in less than reputable activities. Much like the original intent behind 1337 speak itself.

Similar words for divisions of pr0n that are still in use include:
R@ygold - (pedophylia)
qwerty - (bestiality)
showme - (voyuer)
rorikon/lolikon - (anime child)
momashi - (incest)
BBW - (Big Breasted Women)
etc...
Including pr0n in Word_Perfect_help_file_00trpr0n14.pdf makes it hard to realize that the file is actually Tiffany_Shocker.avi renamed; except to the person who masked it of course.
by PuppetSoul July 4, 2004
1337 (leet) for pornography. usually the o is replaced by the digit 0, ie: pr0n.
hey, that's some kickass pr0n.
by Anonymous January 18, 2003
You know when you want to masturbate when you look up porn, you type it in fast and you misspell porn, insted getting pron.
Jack: What are you doing?
Bob: Looking up porn.
Jack: No, your looking up pron.
by AFuckingMotherFucker November 19, 2011
n : film or literature designed to stimulate sexual desire syn: pornography, porno

n.Pornography.

adj.Pornographic.

"pron" or "pr0n" is

An accidental or deliberate misspelling of the word 'porn'. Due to the common misspelling of the word, it has been accepted and encouraged amongst the online gaming community.
It was also used to get around keyword filtering such as in AOL's parental control.
This allowed all the children of the world to have access to all the porn (or pr0n) that is nessessary for a healthy childhood.
"dude, I found some wicked newfangled pr0n on the interweb"
by wormwood January 18, 2004
I was really horny and put pron instead of porn
by BaByboomer January 20, 2012
Pornographic material involving crustaceans. Can be easily obtained on the internet.
by Pyotr Nakariakov July 5, 2011