What it is

The strong side is the side of the formation with more offensive players, usually where the tight end lines up. The weak side is the other side, with fewer players.

In a game

Defenses name their players the same way. The strong safety and the strong-side linebacker, called Sam, line up on the tight end’s side, and the weak-side linebacker, called Will, lines up on the other.

More detail

Offenses sometimes flip their alignment on purpose to move the strong side and force the defense to adjust. A strong side can also change from play to play, so defenders learn to read the formation rather than a fixed side of the field.