A narrow notch, groove, or opening, as in a keyway in machinery or a slit for a coin in a vending machine. Also: the position of a receiver in relation to other defensive positions, especially in a passing play, where he lines up closer to the middle of the field than outside wide receivers.
A slot is a position on the field that is more versatile than other positions, but requires more skill and precision to master. A good Slot receiver will have a strong route tree, be very fast, and be able to run precise routes. He will also be adept at running after the catch and in the open. He will also have to be a very solid blocker on running plays, since he will usually line up close to the middle of the field and will be surrounded by defensive backs, nickelbacks, and safeties.
The Slot is a great position for players who want to play with more of the action, but don’t necessarily have the speed or skills needed to be an outside wide receiver. Because they often line up slightly off the line of scrimmage, Slot receivers are much more agile and flexible than their outside counterparts. They will be able to run more precise, smaller routes and often excel in running after the catch. They will also need to be very effective on running plays, because they are often a vital part of sweeps and slant runs.