noun
: a photometer for comparing the brightness of two lights based upon the principle that flicker between two alternating lights of different color is at a minimum when the brightness of the two is equal
noun
: a photometer for comparing the brightness of two lights based upon the principle that flicker between two alternating lights of different color is at a minimum when the brightness of the two is equal
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012