(ˌ)sərˈkādēən, ¦sərkə¦dēən adjective
Etymology: Latin circa about + di es day + English -an — more at circa deity
: being, having, characterized by, or occurring in approximately 24-hour periods or cycles (as of biological activity or function)
circadian oscillations
circadian periodicity
circadian rhythms in activity
circadian leaf movements
• circadianly adverb