1
- 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。
1.1
- Astronomy a circle passing through the celestial poles and the zenith of a given place on the earth's surface【天文】（天体的）子午线, 经线。
2
- (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。
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.
中天明月。
词源
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.