A slider is a pitch in baseball, sort of halfway between a curveball and a fastball, with less break but more speed than the curve. It will tend to drop less and move toward or away from the batter more than a curve. The extra speed can fool the hitter into thinking it is a fastball, until too late. Some pitchers also use a cut fastball (or cutter) which is one step closer than the slider to the fastball on the spectrum between fastballs and curves. A pitch that has movement similar to both a slider and a curveball is often called a slurve.
