A term in football referring to the side of the field to left or right of the center in the offensive formation with the fewest players. Often, this is the side opposite the tight end. The other side is known as "Strong Side."
This is also referred to as "Back Side."
The normal alignment for an offensive play will have on the line of scrimmage a center, two offensive guards and two offensive tackles. The tight end will be placed next to one of the two tackles. This makes the strong side the side with the tight end and the weak side the opposite side. A strategy with this kind of formation is to run to the weak side if the opposing team is expecting a run to the stronger side. Another way to play this to the most advantage is for the quarterback to run to the strong side and pass to the running back who is now open in the weak side allowing for a big play with less defense from the opposing team.