photoperiod

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photoperiod

 [fo´to-pēr″e-od]
the period of time per day that an organism is exposed to daylight (or to artificial light). adj., adj photoperiod´ic.

photoperiod

(fō′tō-pîr′ē-əd)
n.
The daily duration of light and dark to which an organism is exposed, considered especially with regard to its effect on growth and development.

pho′to·pe′ri·od′ic (-ŏd′ĭk) adj.

photoperiod

the length of daylight as compared with the length of darkness in each 24 hour cycle. see PHOTOPERIODISM.