A running formation by a receiver where the player will run straight down the field and then turn and run toward the center of the field.
Sometimes referred to as a "7 pattern"
Turn in receivers are a special breed because they often catch the ball in the middle of multiple defenders in the middle of the field and they get hit hard after catching the ball. There is a higher potential for fumbling or not being able to catch the ball as the receiver is usually hit right as they catch the ball. Sometimes these turn in patterns are used as decoys to pull defenders away from another receiver who is running a shorter pattern or a longer pattern straight down the sideline.