also: hinge · hinge back
Sealing the space a pulling lineman just left, usually by the tackle stepping down and turning back. The block that stops a pull from opening a hole in your own protection.
When a lineman pulls, he leaves a gap where he was standing, and somebody has to account for it or the play has an unblocked defender in its own backfield. Hinging is the answer: the lineman next to the puller steps down into that space and turns back, swinging like a gate on a hinge, which is where the name comes from.
It is a small assignment that shows up as a disaster when it is missed, because the defender it accounts for arrives exactly where the pulling lineman used to be and exactly where the play is developing.
hingedown block, seal and wall off