pho·​tom·​e·​ter | \ fō-ˈtä-mə-tər How to pronounce photometer (audio) \

Definition of photometer

: an instrument for measuring luminous intensity, luminous flux, illumination, or brightness

Examples of photometer in a Sentence

Recent Examples on the Web So Masson's group is now developing a portable spectral photometer to augment its plasmonic tongue, thereby ensuring accurate readings. Jennifer Ouellette, Ars Technica, "Artificial “tongue” for maple syrup weeds out batches with “buddy” off flavors," 28 May 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'photometer.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of photometer

1779, in the meaning defined above

History and Etymology for photometer

New Latin photometrum, from phot- + -metrum -meter

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Time Traveler for photometer

Time Traveler

The first known use of photometer was in 1779

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Cite this Entry

“Photometer.” Dictionary, Merriam-Webster, Accessed 4 Dec. 2020.

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pho·​tom·​e·​ter | \ fō-ˈtäm-ət-ər How to pronounce photometer (audio) \

Medical Definition of photometer

 (Entry 1 of 2)

: an instrument for measuring the intensity of light, luminous flux, illumination or brightness by comparison of two unequal lights from different sources usually by reducing the illumination of one (as by varying the distance of the source or using a polarizing device) until the two lights appear equal with the amount of adjustment serving as the basis of comparison and the equality of illumination being judged by various means


transitive verb

Medical Definition of photometer (Entry 2 of 2)

: to examine with a photometer

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