photoperiod

noun

pho·​to·​pe·​ri·​od ˌfō-tō-ˈpir-ē-əd How to pronounce photoperiod (audio)
: a recurring cycle of light and dark periods of constant length
photoperiodic adjective
photoperiodically adverb

Examples of photoperiod in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This study opens the door to further insights into just how day length (photoperiod) and sun intensity can impact energy levels and help those with more severe 'winter blues' proactively improve seasonal mental wellbeing. Bronwyn Thompson september 29, New Atlas, 29 Sep. 2024 For example, long-distance migratory songbirds set their internal clocks to the photoperiod and use the summer solstice to time their nesting and migration, said Saeedeh Bani Assadi, a biologist at the University of Manitoba. Quanta Magazine, 18 June 2024 Species have evolved sensitivity to how much light is available in a 24-hour window, and that cue — the photoperiod — has been shown to influence a range of behaviors, from plant growth to hibernation, to migration, and to reproduction. Quanta Magazine, 18 June 2024 Inside the $45 packet were five feminized, photoperiod seeds from Gogol’s Oregon farm, and they can be purchased with no more hassle — or stigma — than anything else at C&S Garden Center. Adam Tschorn, Los Angeles Times, 20 May 2024 The best autoflower seeds for sale also boast a shorter flowering time than photoperiod plants, which means that maintenance time is reduced on your end. Anna Miller, Sacramento Bee, 26 Apr. 2024 On the other hand, there's the findings of sleep psychiatrist Thomas Wehr, in particular his classic 1992 study called In short photoperiods, human sleep is biphasic. Neuroskeptic, Discover Magazine, 29 Apr. 2010 To time this arrival for the highest likelihood of conditions favorable to reproducing, a migratory bird tracks each day’s light length, or photoperiod, says Marilyn Ramenofsky, a behavioral endocrinologist at the University of California, Davis, who specializes in birds. Meghan Bartels, Scientific American, 20 Apr. 2023 As mentioned earlier, brood fish are housed in the same indoor tanks where scientists fool them into spawning by playing around with photoperiods and water temperature. Matt Williams, Dallas News, 9 May 2020

Word History

First Known Use

1920, in the meaning defined above

Time Traveler
The first known use of photoperiod was in 1920

Dictionary Entries Near photoperiod

Cite this Entry

“Photoperiod.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/photoperiod. Accessed 29 Nov. 2024.

Kids Definition

photoperiod

noun
pho·​to·​pe·​ri·​od ˌfōt-ō-ˈpir-ē-əd How to pronounce photoperiod (audio)
: a recurring cycle of light and dark periods as it affects the growth and functioning of a plant or animal

Medical Definition

photoperiod

noun
pho·​to·​pe·​ri·​od ˌfōt-ō-ˈpir-ē-əd How to pronounce photoperiod (audio)
: a recurring cycle of light and dark periods of constant length
photoperiodic adjective
photoperiodically adverb
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!