Diurnal(a.)
- Relating to the daytime; belonging to the period of daylight, distinguished from the night; -- opposed to nocturnal; as, diurnal heat; diurnal hours.
Diurnal(a.)
- 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.
Diurnal(a.)
- Opening during the day, and closing at night; -- said of flowers or leaves.
Diurnal(a.)
- Active by day; -- applied especially to the eagles and hawks among raptorial birds, and to butterflies (Diurna) among insects.