Definition
A slider is a baseball pitch thrown with a grip and wrist action that creates a horizontal, or sideways, break. It’s faster than a curveball but slower than a fastball. The slider can be tough to hit because it looks like a fastball coming out of the pitcher’s hand. Then, at the last moment, it 'slides' to the side. It's like a fastball that suddenly decides to take a detour, fooling the batter.