t0

Commonly read as "tee zero." Internet slang, used primarily by the programming/cracking/hacking crowd – though its use among gamers has become more widespread lately.

Meanings:
1). the beginning
2). since the beginning
3). at the beginning
4). preemptively

Synonyms: all along, from the start, preemptively, beforehand

Origins:

Contrary to the belief of some, the etymology of t0 is probably unrelated to NASA's MET system (see tminus). Rather, it more likely has origins in the statement t = 0, in this case representing the time at which a particular event began.

I knew t0, but didn't tell anyone.
I created a rudimentary map of the area t0 to avoid any potential issues later on.
Looks like they had the game in the bag t0 – we lost before it even began.