light meter vs photometer

light meter and photometer both are nouns.

Word	Noun	Adjective	Verb	Adverb
light meter	Yes	No	No	No
photometer	Yes	No	No	No

As nouns, light meter and photometer are synonyms defined as:

light meter and photometer: photographic equipment that measures the intensity of light

Other synonyms of light meter include exposure meter.

light meter (noun)	photometer (noun)
photographic equipment that measures the intensity of light	photographic equipment that measures the intensity of light
	measuring instrument for measuring the luminous intensity of a source by comparing it (visually or photoelectrically) with a standard source