meridian

Definitions

General English

Astronomy

Aviation

  • noun an imaginary great circle on the Earth’s surface passing through the north and south geographic poles

Electronics

  • An imaginary great circle along the surface of the planet which passes through both geographic poles. All points along a given meridian have the same longitude, with the prime meridian passing through longitude 0°. Also, a great half-circle joining both geographic poles.
  • An imaginary great circle along the surface of a celestial body which passes through both its geographic poles, or that joins them.

Medical

  • noun in acupuncture and Chinese medicine, one of the pathways in the body along which its energy is believed to flow

Origin & History of “meridian”

Etymologically, meridian denotes the ‘middle of the day’. It comes via Old French from Latin merīdiānus, a derivative of merīdiēs ‘mid-day’. this was an alteration of an earlier medidiēs, a compound noun formed from medius ‘middle’ (source of English medium) and diēs ‘day’. The application of the word to a circle passing round the earth or the celestial sphere, which is an ancient one, comes from the notion of the sun crossing it at noon.
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