The beltline is the visual and structural boundary running horizontally along the side of a vehicle, separating the lower body panels from the glasshouse and roof pillars. Designers manipulate the height of this line to alter a car's proportions, while body technicians use it as a primary reference point for aligning replacement panels and checking structural straightness.
Heard on the job
The door skin is buckled right below the beltline, so we'll have to pull it before sanding.