photoperiod

[ foh-tuh-peer-ee-uhd ]

noun

, Biology.

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

photoperiod

/ ˌfəʊtəʊˈpɪərɪəd /

noun

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

photoperiod

/ fō′tō-pîr′ē-əd /

1. The duration of an organism's daily exposure to light, considered especially with regard to the phenomena of photoperiodism.

Derived Forms

• ˌphotoˌperiˈodically, adverb
• ˌphotoˌperiˈodic, adjective

Other Words From

• pho·to·pe·ri·od·ic [foh-t, uh, -peer-ee-, od, -ik], photo·peri·odi·cal adjective
• photo·peri·odi·cal·ly adverb

Word History and Origins

Origin of photoperiod¹

First recorded in 1915–20; photo- + period

Example Sentences

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.

From Los Angeles Times

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.

From Los Angeles Times

The LWD1 mutation thus makes barley virtually insensitive to photoperiod, which in turn makes cultivation in various latitudes and marginal environments with sub-optimal growing conditions possible.

From Science Daily

"Moreover, biological factors that are known to affect birth seasonality -- such as photoperiod exposure, temperature, humidity, and availability of food -- also depend on socio-demographic characteristics, since different social groups are exposed to these biological factors to varying degrees," Professor Borrell, a social epidemiologist at the City University's Department of Epidemiology & Biostatistics, Graduate School of Public Health & Health Policy, says.

From Science Daily

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.

From Scientific American