Trisec
From Memory Alpha, the free Star Trek reference.
A trisec is unit of time on the planet Triskelion.
Fifteen trisecs is roughly equal to forty-five seconds on the planet Earth, so it can be inferred that the term "trisec" is literal (if abbreviated) and, in fact, equals three Earth seconds. (TOS: "The Gamesters of Triskelion")
