[ foh-toh-kem-uh-stree ]
/ ˌfoʊ toʊˈkɛm ə stri /


the branch of chemistry that deals with the chemical action of light.

Nearby words

  1. photocatalyst,
  2. photocathode,
  3. photocell,
  4. photochemical,
  5. photochemical smog,
  6. photochemotherapy,
  7. photochromic,
  8. photochromic lens,
  9. photochromy,
  10. photochronograph

Origin of photochemistry

First recorded in 1865–70; photo- + chemistry

Related formspho·to·chem·i·cal [foh-toh-kem-i-kuh l] /ˌfoʊ toʊˈkɛm ɪ kəl/, pho·to·chem·ic, adjectivepho·to·chem·i·cal·ly, adverbpho·to·chem·ist, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for photochemical

  • Scheele's work aroused much interest in photochemical effects and many investigations followed.

    Artificial Light|M. Luckiesh
  • The foregoing are only a few of the multitude of photochemical reactions and other effects of radiant energy.

    Artificial Light|M. Luckiesh
  • The product of photochemical decomposition no longer forms azo-colours with amines or phenols.

    Coal|Raphael Meldola
  • We must therefore conclude that the heliotropic curvature of the polyps is determined by a photochemical action of the light.

British Dictionary definitions for photochemical


/ (ˌfəʊtəʊˈkɛmɪkəl) /


of or relating to photochemistry; involving the chemical effects of light
Derived Formsphotochemically, adverb


/ (ˌfəʊtəʊˈkɛmɪstrɪ) /


the branch of chemistry concerned with the chemical effects of light and other electromagnetic radiationsAlso called: actinochemistry
Derived Formsphotochemist, noun

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

Medicine definitions for photochemical


[ fō′tō-kĕmĭ-strē ]


The branch of chemistry that deals with the effects of light on chemical systems.
Related formspho′to•chemi•cal (-ĭ-kəl) adj.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for photochemical


[ fō′tō-kĕmĭ-strē ]

The scientific study of the effects of light and ultraviolet radiation on chemical reactions.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.