diurnal Meaning, Definition & Usage

adjective of or belonging to or active during the day
- diurnal animals are active during the day
- diurnal flowers are open during the day and closed at night
- diurnal and nocturnal offices
adjective satellite having a daily cycle or occurring every day
- diurnal rotation of the heavens

L. diurnalis, fr. dies day. See Deity, and cf. Journal.

Relating to the daytime; belonging to the period of daylight, distinguished from the night; -- opposed to nocturnal; as, diurnal heat; diurnal hours.
Daily; recurring every day; performed in a day; going through its changes in a day; constituting the measure of a day; as, a diurnal fever; a diurnal task; diurnal aberration, or diurnal parallax; the diurnal revolution of the earth.
Ere twice the horses of the sun shall bring Their fiery torcher his diurnal ring. Shak.
(Bot.) Opening during the day, and closing at night; -- said of flowers or leaves.
(Zoöl.) Active by day; -- applied especially to the eagles and hawks among raptorial birds, and to butterflies (Diurna) among insects. Syn. -- See Daily.

Cf. F. diurnal a prayerbook. See Diurnal, a.

A daybook; a journal. Obs. Tatler.
(R. C. Ch.) A small volume containing the daily service for the "little hours," viz., prime, tierce, sext, nones, vespers, and compline.
(Zoöl.) A diurnal bird or insect.