An MKS unit of luminance, equal to one candela per square meter, or 10-4 stilb. The nit is not approved as part of the SI, but it has been approved since 1947 by the International Commission on Illumination (CIE) and is in wide use. The name of the unit comes from the Latin niteo, to shine. This unit is sometimes called the meterlambert, by analogy with the footlambert