Answer: circadian

AnswerCrossword Clue
circadianoccurring every twenty-four hours
circadiannoting or pertaining to rhythmic biological cycles recurring at approximately 24-hour intervals.
circadianbeing, having, characterized by, or occurring in approximately 24-hour periods or cycles (as of biological activity or function) circadian rhythms in activity
circadiannoting or pertaining to rhythmic biological cycles recurring at approximately 24-hour intervals