A Microt is a unit of time. One Microt is equal to about one second. A comparison appears in episode 2.04 "Crackers Don't Matter".
Pilot counts down 10 Microts towards the end of episode 2.21 "Liars, Guns & Money - Plan B"
In episode 1.12 "The Flax", Crichton says 4 minutes equals 180 microts. That means a microt is 1.333 seconds.