Adjective: diurnal dI'ur-n(u)l
- (biology) of or belonging to or active during the day
"diurnal and nocturnal offices"; "diurnal animals are active during the day"; "diurnal flowers are open during the day and closed at night"
- Having a daily cycle or occurring every day
"diurnal rotation of the heavens"
See also: periodic, periodical
Antonym: nocturnal
Encyclopedia: Diurnal