Leet (or "1337"), also known as eleet or leetspeak, is an alternative alphabet for the English language that is used primarily on the Internet. It uses various combinations of ASCII characters to replace Latinate letters. For example, leet spellings of the word leet include 1337 and l33t; eleet may be spelled 31337 or 3l33t.
The term leet is derived from the word elite. The leet alphabet is a specialized form of symbolic writing. Leet may also be considered a substitution cipher, although many dialects or linguistic varieties exist in different online communities. The term leet is also used as an adjective to describe formidable prowess or accomplishment, especially in the fields of online gaming and in its original usage, computer hacking.
Leet originated within bulletin board systems in the 1980s, where having "elite" status on a bulletin board system (BBS) allowed a user access to file folders, games, and special chat rooms. One theory is that it was developed to defeat text filters created by BBS or Internet Relay Chat system operators for message boards to discourage the discussion of forbidden topics, like cracking and hacking. Creative misspellings and ASCII-art-derived words were also a way to attempt to indicate one was knowledgeable about the culture of computer users. Once the reserve of hackers, crackers, and script kiddies, leet has since entered the mainstream. It is now also used to mock newbies, or newcomers, on web sites, or in gaming communities. Some consider emoticons and ASCII art, like smiley faces, to be leet, while others maintain that leet consists of only symbolic word encryption. More obscure forms of leet, involving the use of symbol combinations and almost no letters or numbers, continue to be used for its original purpose of encrypted communication. It is also sometimes used as a script language. Variants of leet have been used for censorship purposes for many years; for instance "@$" and "$#!+" are frequently seen to make a word appear censored to the untrained eye but obvious to a person familiar with leet.