A type of receiver in football that lines up behind the line of scrimmage, usually on the side of the tight end and the opposite side of the split end. This type of receiver is also known as a "flanker" or "wide receiver". In a certain position, the Z receiver will also be referred to as a "slot back".
A Z receiver will be lined up off the line of scrimmage. Due to his speed, the Z receiver will get to catch a large number of passes. Secondly, the Z receiver's position on the right side of the quarterback means that a right-handed quarterback will pass to him instead of across his body to another receiver. During a running play, the Z receiver will have the responsibility of blocking defenders. A Z receiver can be placed in the position between the split end and the left tackle, at which time he will be referred to as a "slot back". Even though the Z receiver is referred to as a "slot back" in this position, the Z receiver still has the exact same responsibility.