A slot is a narrow notch, groove, or opening, as in the journal of a screw-driver shaft or the slit for a coin in a vending machine. The term may also refer to a position in a group, series, or sequence.
Slot Receivers – NFL
As offenses have moved toward more 3-1 receiver/back formations in recent seasons, the slot position has become increasingly important. Essentially, the Slot receiver lines up pre-snap between the last man on the line of scrimmage (usually either the tight end or offensive tackle) and the outside wide receiver. Slot receivers are usually smaller than traditional wide receivers and can stretch defenses vertically off of speed, but they’re also able to catch and run shorter routes like slants and quick outs. They’re also a vital blocker for the ball carrier on running plays. Consequently, the Slot receiver is a valuable weapon for any offense.