There are 2 main definitions of meridian in English:

meridian1

Syllabification: me·rid·i·an
Pronunciation: /məˈridēən
 
/

noun

1A circle of constant longitude passing through a given place on the earth’s surface and the terrestrial poles.
More example sentences
  • Whereas terrestrial longitude uses meridians of longitude, right ascension uses hour circles which run between the north and south celestial poles.
  • The first part described geographical and astronomical terms such as latitude, longitude, meridian, poles, eclipses, signs of the zodiac etc.
  • Whereas meridians of longitude loop, from the North Pole to the South and back again, in great circles of the same size, converging at the ends of the earth.
1.1 (also celestial meridian) Astronomy A circle passing through the celestial poles and the zenith of a given place on the earth’s surface.
More example sentences
  • It will be the start of a new era resulting from and signified by the solar meridian crossing the galactic equator, and the earth aligning itself with the center of the galaxy.
  • Local time at all other locations on the Earth's surface is based on the Sun's position relative to the celestial meridian, an imaginary line running north and south directly overhead.
  • The nearest part of the Earth's surface to the Moon, around the noon meridian, may be only just close enough to be within the umbra (the conical lunar shadow), so that observers there experience a very brief total eclipse.
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.
More example sentences
  • Acupuncture, which originated in China more than 2,000 years ago, is based on the idea that energy, or Qi, flows along channels called meridians in body.
  • This flows between the organs of the body along pathways called meridians or channels.
  • It has its basis in traditional Chinese medicine, and uses the same principles of energy and meridians as acupuncture or acupressure.

adjective

[attributive] Back to top  
1Relating to or situated at a meridian: the meridian moon
More example sentences
  • Another of ibn Sina's contributions to astronomy was his attempt to calculate the difference in longitude between Baghdad and Gurgan by observing a meridian transit of the moon at Gurgan.
  • ‘I was really struggling with the treatment I was on, but I've been trying meridian therapy since then and I feel a lot better,’ said Helen, of Lowther Street.
  • Putting years of training into learning how to apply hypnotic and meridian therapies is quite a dramatic departure for the father-of-three after running a regional building society for much of his life.
1.1 literary Of noon.
1.2 literary Of the period of greatest splendor, vigor, etc.

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.

Definition of meridian in:

There are 2 main definitions of meridian in English:

Meridian2

Syllabification: Me·rid·i·an
Pronunciation: /məˈridēən
 
/
1A city in southwestern Idaho, west of Boise; population 66,916 (est. 2008).
2A city in eastern Mississippi; population 38,232 (est. 2008).