A slider is a type of pitch in baseball that moves sideways as it approaches home plate, making it harder to hit. While a fastball travels in a relatively straight line, a slider breaks sharply to the left or right just before reaching the batter. This sideways movement happens because of the way the pitcher grips and releases the ball, creating spin that makes it curve through the air.

The slider is one of the trickiest pitches for batters to handle. From the pitcher's hand, it looks like it might be a strike, but then it suddenly slides away from the bat at the last moment. A good slider can make even excellent hitters swing and miss, or hit weak grounders. Pitchers often throw sliders when they need a strikeout in an important situation.

The word slider also refers to a small hamburger, usually about half the size of a regular burger. Restaurants often serve sliders in groups of two or three so people can try different flavors. These mini burgers got their name because they're small enough to eat in just a few bites and easy to eat quickly.