A type of receiver in football who lines up between the split end ("X receiver") and flanker ("Z receiver") and the center and is eligible to receive the ball. This type of receiver is also known as a "slot receiver" or "tight end".
A Y receiver will be lined up between the split end or the flanker and the linemen. The position on the field is determined by which of the other receivers the Y receiver is paired up with. If paired with a flanker, the Y receiver will be on the scrimmage line. If paired with a split end, the Y receiver will be off the line of scrimmage.
Y receivers specialize in either catching the ball and being an outlet receiver or blocking and being part of the running game. As an outlet receiver, the Y receiver will catch the ball should the quarterback not have the time to find a receiver. For a Y receiver in the running game, the priority will be to block and open a path to the runner with the ball.