Photometer

n.

1.

(Physics) An instrument for measuring the intensity of light, or, more especially, for comparing the relative intensities of different lights, or their relative illuminating power.

Noun	1.	photometer - measuring instrument for measuring the luminous intensity of a source by comparing it (visually or photoelectrically) with a standard source
	2.	photometer - photographic equipment that measures the intensity of light Synonyms: exposure meter, light meter

measuring device, measuring instrument, measuring system, spectrophotometer