noun (used with a singular verb)
the science dealing with light and its effects on living organisms.
Origin of photodynamics
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(functioning as singular) the branch of biology concerned with the effects of light on the actions of plants and animals
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
The science that deals with the activating effects of light on living organisms.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
The scientific study of the effects of light on organic compounds and on the metabolisms of living things.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.