the interval in a 24-hour period during which a plant or animal is exposed to light.
Origin of photoperiod
Related formspho·to·pe·ri·od·ic [foh-tuh-peer-ee-od-ik] /ˌfoʊ təˌpɪər iˈɒd ɪk/, pho·to·pe·ri·od·i·cal, adjectivepho·to·pe·ri·od·i·cal·ly, adverb
First recorded in 1915–20; photo-
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for photoperiod
Historical Examples of photoperiod
British Dictionary definitions for photoperiod
Derived Formsphotoperiodic, adjectivephotoperiodically, adverb the period of daylight in every 24 hours, esp in relation to its effects on plants and animalsSee also photoperiodism
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
Related formspho′to•pe′ri•od′ic (-ŏd′ĭk) null adj.
The duration of an organism's daily exposure to light, considered especially with regard to the effect of such exposure on growth and development.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
The duration of an organism's daily exposure to light, considered especially with regard to the phenomena of photoperiodism.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.