'Diurnal arc' definitions:

Definition of 'Diurnal arc'

From: GCIDE
  • 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. (Zool.) 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]