Movement Speed is the measure of how quickly the character can move. This is a number of feet that can be traveled in 1 second intervals.
Movement speed is $10+RT$, with RT being Response Time. Usually MS is not directly altered, though it can be. It can also be temporarily raised by skills and permanently increased by traits. The fastest human official record has been 34 feet per second, so MS of 34, which is nearly twice the base rate.