circadianPronunciation: /səːˈkeɪdɪən/Definition of circadian adjective Physiology (of biological processes) recurring naturally on a twenty-four-hour cycle, even in the absence of light fluctuations:a circadian rhythmOrigin: 1950s: formed irregularly from Latin circa 'about' + dies 'day'circadian in other Oxford dictionaries Definition of circadian in the US English dictionary
