a circle of constant longitude passing through a given place on the earth's surface and the terrestrial poles (地球的)子午线,经线 ■(Astronomy)a circle passing through the celestial poles and the zenith of a given place on the earth's surface (天文)(天球的)子午线,经线
(in acupuncture and Chinese medicine) each of a set of pathways in the body along which vital energy is said to flow. There are twelve such pathways associated with specific organs (针灸及中医用语)经脉
adjective
[attrib.]relating to or situated at a meridian (与)子午线(有关)的,(与)经线(有关)的;在子午线的 the meridian moon. 月在中天。
语源
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