The name t0s is the abbreviation of "The Old School". In the past, in a world where underground technology of today was not invented, the hacking was based in things how: "Default Passwords", "Wardialing", "X25", "Sniffers", "Bruteforcing", "Rootkits".

The reason for this name is because nowadays there are some things that are continued to do like "The Old School" but others don't. The t0s group merge the two styles and create his own way of hack.