leet (1337, eleet)
jargonhackingops culture
Elite, spelled the way the bulletin-board underground spelled it: letters replaced by digits and symbols, 3 for E, 1 for L, 7 for T. 31337 is eleet, and remains a running joke that shows up as port numbers, version strings and CTF flags.
The orthography began as evasion - keyword filters on BBSs looking for forbidden words - and hardened into an in-group marker: writing it fluently proved you belonged, overusing it proved the opposite. It gave the field a vocabulary that survives in earnest, from pwn to the 1337 port. Understanding the register matters when reading old files, because a text that looks like noise is often precise technical writing wearing a costume.
Also known as: 1337, l33t, eleet, leetspeak, 31337