Biol. designating or of behavioral or physiological rhythms associated with the 24-hour cycles of the earth's rotation, as, in man, the regular metabolic, glandular, and sleep rhythms which may persist through a dislocation of day and night caused by high-speed travel
Origin of circadiancoined from Classical Latin circa, about + diem, accusative singular of dies, day: see deity
Relating to or exhibiting approximately 24-hour periodicity.
Origin of circadianLatin circā around ; see circa . Latin diēs day ; see dyeu- in Indo-European roots.
(comparative more circadian, superlative most circadian)