1. The length of time each day that an organism is exposed to light, especially as it affects biological processes such as flowering, migration, or reproduction.
Usage: Plural form of photoperiod; Commonly used in biology, botany, and ecology

Examples

• Plants respond to changing photoperiods to determine when to flower in spring or fall.
• Different photoperiods trigger migration patterns in many bird species.
• The greenhouse uses artificial lighting to manipulate photoperiods for year-round crop production.
• Photoperiods vary significantly between tropical and temperate regions.
• Scientists study how photoperiods affect the circadian rhythms of animals.
• Long photoperiods in summer stimulate growth in many plant species.