Such that. Commonly used in the field of mathematics and less so in science. It demonstrates that a condition is necessary in a cause-and-effect manner.
Stacey dawned a heavyjacket s.t. she could better handle the torrential downpour on her way to the market.
Idiotic way of writing shit as to not be offensive, as if anyone couldn't figure out what it said. Other forms include sh*t (even more obvious) and s***