- The definition of diurnal is something that happens daily or in the daytime.
An example of something diurnal is a diurnal flower that blooms in the sunlight, but closes at night.
- occurring each day; daily
- of, done, or happening in the daytime
- Bot. opening in the daytime and closing at night: said of a flower
- Zool. active in the daytime
Origin of diurnalMiddle English ; from Classical Latin diurnalis ; from diurnus, daily ; from dies, day: see deity
- Archaic a daily newspaper
- Eccles. a service book containing prayers for the daytime canonical hours and for compline
- Relating to or occurring in a 24-hour period; daily.
- Occurring or active during the daytime rather than at night: diurnal animals.
- Botany Opening during daylight hours and closing at night.
- A book containing all the offices for the daily canonical hours of prayer except matins.
- Archaic a. A diary or journal.b. A daily newspaper.
Origin of diurnalMiddle English, from Late Latin diurnālis, from Latin diurnus, from diēs, day; see dyeu- in Indo-European roots.
- Happening or occurring during daylight, or primarily active during that time.
- Most birds are diurnal.
- (botany) Said of a flower open, or releasing its perfume during daylight hours, but not at night.
- Having a daily cycle that is completed every 24 hours, usually referring to tasks, processes, tides, or sunrise to sunset.
- (uncommon) Done once every day; daily, quotidian.
- (archaic) Published daily.