Circadian

Origin

From the Latin circā ("about") and diēs ("a day") with the English suffix -an. Compare circannual.

Full definition of circadian

Adjective

1. (biology) of, relating to, or showing rhythmic behaviour with a period of 24 hours; especially of a biological process
• 2000, Arnold Sameroff, et al., Handbook of Developmental Psychopathology, page 310The circadian clock is involved in the regulation of the diurnal sleep-wake cycle, ….
• 2002, Jill B. Becker, Behavioral Endocrinology, page 483To summarize, the circadian system, particularly the SCN, controls the circadian pattern of melatonin release in mammals.
• 2005, Paul Martin, Counting Sheep: The Science and Pleasures of Sleep and Dreams, page 114The most obvious circadian rhythm is the daily cycle of sleep and activity.

Derived terms

• circadian rhythm