Definitions

1. adjective

relating to or characteristic of the timekeeping system in living organisms, especially the periodic changes in bodily functions and physiological processes that follow a roughly 24-hour cycle

“The researchers studied the circadian rhythms of nocturnal animals to understand their sleep patterns.”

2. noun

a periodic change in bodily functions and physiological processes that follow a roughly 24-hour cycle

“The effects of jet lag on the circadian rhythm can be significant.”