A repeating wave-like departure from flatness produced as softened glass travels over rollers during horizontal heat treatment.
GlassRenu media library · Image source · Image source
Meaning and boundaries
Roll wave is not a scratch, haze, stain, coating defect, or general bow of the whole lite.
Why it matters in glass restoration
It can affect reflected images and visual evaluation, and it should not be misclassified as restorable surface damage.