[ foh-tuh-peer-ee-uhd ]

  1. the interval in a 24-hour period during which a plant or animal is exposed to light.

Origin of photoperiod

First recorded in 1915–20; photo- + period

Other words from photoperiod

  • pho·to·pe·ri·od·ic [foh-tuh-peer-ee-od-ik], /ˌfoʊ təˌpɪər iˈɒd ɪk/, pho·to·pe·ri·od·i·cal, adjective
  • pho·to·pe·ri·od·i·cal·ly, adverb

Words Nearby photoperiod Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use photoperiod in a sentence

British Dictionary definitions for photoperiod


/ (ˌfəʊtəʊˈpɪərɪəd) /

  1. the period of daylight in every 24 hours, esp in relation to its effects on plants and animals: See also photoperiodism

Derived forms of photoperiod

  • photoperiodic, adjective
  • photoperiodically, adverb

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

Scientific definitions for photoperiod


[ fō′tō-pîrē-əd ]

  1. 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.