photoperiod
noun
pho·to·pe·ri·od
ˌfō-tō-ˈpir-ē-əd 
: a recurring cycle of light and dark periods of constant length
also
: photophase sense 2
Examples of photoperiod in a Sentence
Recent Examples on the Web
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
These examples are automatically compiled from online sources to
illustrate current usage. Opinions expressed in the examples do not represent those of
Merriam-Webster or its editors.
Send us feedback
about these examples.
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
Dictionary Entries Near photoperiod
Cite this Entry
“Photoperiod.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/photoperiod. Accessed 20 Nov. 2024.
Copy CitationKids Definition
photoperiod
noun
pho·to·pe·ri·od
ˌfōt-ō-ˈpir-ē-əd
: 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
: a recurring cycle of light and dark periods of constant length
Love words? Need even more definitions?
Merriam-Webster unabridged
Share