Dictionary.com
definitions

photocatalysis

[foh-toh-kuh-tal-i-sis]
noun, plural pho·to·ca·tal·y·ses [foh-toh-kuh-tal-i-seez] /ˌfoʊ toʊ kəˈtæl ɪˌsiz/. Chemistry.
  1. the acceleration or retardation of the reaction rate in chemical reactions by light.

Origin of photocatalysis

First recorded in 1910–15; photo- + catalysis
Related formspho·to·cat·a·lyt·ic [foh-toh-kat-l-it-ik] /ˌfoʊ toʊˌkæt lˈɪt ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for photocatalysis

photocatalysis

noun plural -ses (-siːz)
  1. the alteration of the rate of a chemical reaction by light or other electromagnetic radiation
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