meridian

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

• relating to or situated at a meridian:the meridian moon