Term

Perimeter

The perimeter is the outer edge of the haircut, such as the hemline at the bottom and the lines around the face. It matters in a shag because many stylists keep the perimeter reasonably full and concentrate layers higher up, especially on fine hair, which can look see-through if the ends are cut too aggressively. A long shag in particular depends on a connected perimeter so the layers do not look disconnected from the length. See also: Weight line, Feathering, Layers, and the guide Shag Haircuts for Fine and Thick Hair: Density Matters.