watt per steradian per square meter "A radiance unit which is equal to one watt of radiant power incident per steradian solid angle per one square meter projected area of the source, as viewed from the given direction." [NIST:NIST] W/sr m^[2] watt per steradian per square metre watt per steradian per square meter based unit watt per steradian per square meter "A radiance unit which is equal to one watt of radiant power incident per steradian solid angle per one square meter projected area of the source, as viewed from the given direction." [NIST:NIST] W/sr m^[2] watt per steradian per square metre