meridian

 
Pronunciation: /məˈrɪdɪən/

noun

  • 1a circle of constant longitude passing through a given place on the earth’s surface and the terrestrial poles: the European Broadcasting Area extends from the Atlantic to the meridian 40°E
  • Astronomy a circle passing through the celestial poles and the zenith of a given place on the earth’s surface: at the end of February Jupiter transits the meridian, due south, at 6.15 a.m.
  • 2(in acupuncture and Chinese medicine) each of a set of pathways in the body along which vital energy is said to flow: the slow movements and postures of t’ai chi open up and align the meridians of the body

adjective

[attributive]
  • relating to or situated at a meridian: the meridian moon

Origin:

late Middle English: from Old French meridien, from Latin meridianum (neuter, used as a noun) 'noon', from medius 'middle' + dies 'day'. The use in astronomy is due to the fact that the sun crosses a meridian at noon