circadian rhythm
[ sər-kā′dē-ən ]
A daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the alternation of night and day. Circadian rhythms include sleeping and waking in animals, flower closing and opening in angiosperms, and tissue growth and differentiation in fungi. See also biological clock.
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Words Nearby circadian rhythm
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
How to use circadian rhythm in a sentence
Lighting signals your body's circadian rhythm and can have a strong effect on your mood.
“One of the most important things you can do for your sleep is to have a routine to keep your circadian rhythm normal,” says Suh.
Cultural definitions for circadian rhythm
[ (suhr-kay-dee-uhn) ]
An activity cycle lasting twenty-four hours. Many living things, including humans, follow a circadian rhythm. (See biological clock.)
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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