Leet
Leet (sometimes written as "1337" or "l33t"), also known as eleet or leet-speak, is another alphabet for the English language that is used mostly 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. It is used on the internet in forums, chat rooms and online games.