Seam route
The seam route is a route, usually played against a zone defense in American football, in which the receiver runs at the edges of a defender's coverage, thus, on the "seam" between two or more coverages. It is not a route on its own, but the location of another route. The seam is the area where two defenders' areas of responsibility meet. The concept behind this is that the ability to complete a pass is increased because the defenders may be confused about which one of them is responsible for defending the player on the seam or; the defenders are trying to cover their area of responsibility which creates an open space equidistant between the defenders.