DIURNAL By N., Sam M.S. - 2 Means daily or recurring every 24 hours and active during daylight. See biological clock- circadian rhythm. Compare nocturnal. DIURNAL: "We live a diurnal lifestyle." Related Psychology Terms ADOLESCENCE (Theories) PHASE SHIFT VISIBILITY CURVE DREAM-STATE (D-STATE, REM- STATE) SUPRACHIASMATIC NUCLEUS (SCN) LYSERGIC ACID (LSD) BIOLOGICAL RHYTHM Piaget’s Theory of Cognitive Development HYPERMNESIA HUNGER DRIVE Cite this page: N., Sam M.S., "DIURNAL," in PsychologyDictionary.org, April 7, 2013, https://psychologydictionary.org/diurnal/ (accessed December 5, 2021).