diurnal
Active by day
Diurnal means occurring during the day or in a daily cycle.
A diurnal animal is active by day and sleeps at night—the opposite of nocturnal.
In technical contexts, diurnal describes any phenomenon with a 24-hour period: diurnal temperature variation, diurnal tides.
The word appears mainly in scientific writing; everyday English prefers daily.
Per diem, repeated
- daylightSun's natural glow
- daytimeSunlit portion of day
- sunriseMorning light's arrival
- sunsetDay yielding to darkness
dawn · dusk · noon · midday · morning · afternoon · twilight · photoperiod
Circadian rhythm regulator
- cortisolAdrenal steroid regulating stress
- sleep-wakeDaily rest-activity pattern
- alertnessActive mental awareness
- wakefulnessState of being conscious
drowsiness · jet lag · chronotype · body clock · metabolism · hormone · temperature · peak
Light-to-sugar conversion in plants
- chlorophyllLight-harvesting plant pigment
- solarOf the star
- sunshineDirect rays from above
- sunbeamShaft of daylight
ultraviolet · vitamin D · daybreak · glare · brightness · warmth · exposure · shadow
daily
Per diem, repeated
sunset · dawn · dusk · noon · midday · morning · afternoon · twilight · photoperiod · light-dark
melatonin
Circadian rhythm regulator
- cortisolAdrenal steroid regulating stress
- sleep-wakeDaily rest-activity pattern
- alertnessActive mental awareness
wakefulness · drowsiness · jet lag · chronotype · body clock · metabolism · hormone · temperature · peak · trough
photosynthesis
Light-to-sugar conversion in plants
- chlorophyllLight-harvesting plant pigment
- solarOf the star
- sunshineDirect rays from above
sunbeam · ultraviolet · vitamin D · daybreak · glare · brightness · warmth · exposure · shadow · shade
crepuscular
Relating to dusk
moth · pollinator · foraging · migration · feeding · predator · prey · activity · behavioral · dormancy
schedule
Plan of timed events
- habitSettled regular tendency
- patternRecurring arrangement or template
- ritualCeremonial set of actions
regimen · breakfast · lunch · dinner · commute · workday · chores · errands · hygiene · exercise
- adaptationnatural selection, evolution, mimicry, camouflage, hibernation
- astrologyastrology, zodiac, horoscope, horoscopes, birth chart
- biology termscell, DNA, genetics, genetic, evolution
- zoologymammals, reptiles, amphibians, birds, insects
- activity patternsmorning routine, daily routine, sleep schedule, work schedule, eating habits
- daytimedawn, daylight, daytime, midday, morning
diurnalsporadic
Occurring irregularly, infrequently
irregular · erratic · occasional · nonperiodic · spasmodic