Circadian
sɜrˈkeɪ.di.ən
adjective
relating to or recurring at approximately 24-hour intervals
The term 'circadian' is derived from the Latin words 'circa' (which means 'around') and 'diem' (which means 'day'). Circadian rhythms are natural processes that follow a daily cycle, such as the sleep-wake cycle in humans.
See how Frank Herbert uses "circadian", with its meaning, pronunciation and a real book example.
Examples from books
The infallible mental clock that had been set ticking during the Spice Agony told her she had adapted to the planet's circadian rhythms.
Frank Herbert
Chapterhouse: Dune
