a unit of luminance in the centimeter-gram-second system of units. The stilb is abbreviated sb. It is equal to the luminance of a uniformly radiating flat surface of area 1 cm² in the direction perpendicular to the surface when the luminous intensity is 1 candela (cd). The relation between the stilb and the unit of luminance in the International System of Units, the cd/m², is 1 sb = 10⁴ cd/m². The stilb has practically gone out of use.