noun Optics.

an instrument that measures luminous intensity or brightness, luminous flux, light distribution, color, etc., usually by comparing the light emitted by two sources, one source having certain specified standard characteristics.

Origin of photometer

From the New Latin word photometrum, dating back to 1770–80. See photo-, -meter Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for photometer

actinometer, radiometer

Examples from the Web for photometer

Historical Examples of photometer

  • An application of the law of intensity is made in using a simple (Bunsen) photometer.


    Willis Eugene Tower

  • The photometer or instrument for accurate comparison of lights, their amount and intensity, tells a different story.


    David Todd

  • A valve is then fitted to one of the front openings, so that the light in that half of the photometer may be gradually diminished.

    A Color Notation

    Albert H. Munsell

  • There is no other way of measuring the exposure than by the photometer or personal experience, and the latter is by far the best.

  • A number of measurements of the illuminating power of an electric lamp were rapidly made during the lecture with this photometer.

British Dictionary definitions for photometer



an instrument used in photometry, usually one that compares the illumination produced by a particular light source with that produced by a standard sourceSee also spectrophotometer
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012