Found 1 items, similar to diurnal arc.
English → English (gcide) Definition: Diurnal arc Diurnal \Di*ur"nal\, a. [L. diurnalis, fr. dies day. See Deity, and cf. Journal.] 1. Relating to the daytime; belonging to the period of daylight, distinguished from the night; -- opposed to nocturnal; as, diurnal heat; diurnal hours. [1913 Webster] 2. 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. [1913 Webster] Ere twice the horses of the sun shall bring Their fiery torcher his diurnal ring. --Shak. [1913 Webster] 3. (Bot.) Opening during the day, and closing at night; -- said of flowers or leaves. [1913 Webster] 4. (Zo["o]l.) Active by day; -- applied especially to the eagles and hawks among raptorial birds, and to butterflies (Diurna) among insects. [1913 Webster] Diurnal aberration (Anat.), the aberration of light arising from the effect of the earth's rotation upon the apparent direction of motion of light. Diurnal arc, the arc described by the sun during the daytime or while above the horizon; hence, the arc described by the moon or a star from rising to setting. Diurnal circle, the apparent circle described by a celestial body in consequence of the earth's rotation. Diurnal motion of the earth, the motion of the earth upon its axis which is described in twenty-four hours. Diurnal motion of a heavenly body, that apparent motion of the heavenly body which is due to the earth's diurnal motion. Diurnal parallax. See under Parallax. Diurnal revolution of a planet, the motion of the planet upon its own axis which constitutes one complete revolution. Syn: See Daily. [1913 Webster]