1. an imaginary great circle on the earth's surface passing through the north and south geographic poles. all points on the same meridian have the same longitude.
2. either half of such a great circle from pole to pole.
3. astronomy A great circle passing through the two poles of the celestial sphere and the zenith of a given observer.
4. mathematics A curve on a surface of revolution, formed by the intersection of the surface with a plane containing the axis of revolution.
5. mathematics A plane section of a surface of revolution containing the axis of revolution.
6. any of the longitudinal lines or pathways on the body along which the acupuncture points are distributed.
7. archaic the highest point in the sky reached by the sun or another celestial body; a zenith.
8. archaic noon.
9. the highest point or stage of development; peak: "men come to their meridian at various periods of their lives” ( john henry Newman).
10. midwestern U.S. see median strip. see regional note at neutral ground.
11. of or relating to a meridian; meridional.
12. of or at midday: the meridian hour.
13. of, relating to, or constituting the highest point, as of development or power: the empire in its meridian period.

1. an imaginary great circle on the earth's surface, passing through the geographic poles.
2. either half of such a great circle, all points of which have the same longitude.
3. A great circle passing through the poles of the celestial sphere and the zenith for a particular observer.
4. A similar line on any general surface of revolution.
5. any of the pathways on the body along which the vital energy is thought to flow and, therefore, the acupoints are distributed.
6. the highest point or state of consciousness and enlightenment achievable by a human.
7. meridional; relating to a meridian.
8. relating to noon

1. being at, or pertaining to, midday; belonging to, or passing through, the highest point attained by the sun in his diurnal course.
2. pertaining to the highest point or culmination.
3. midday; noon.
4. hence: the highest point, as of success, prosperity, or the like; culmination.
5. A great circle of the sphere passing through the poles of the heavens and the zenith of a given place. it is crossed by the sun at midday.
6. A great circle on the surface of the earth, passing through the poles and any given place; also, the half of such a circle included between the poles.

1. of or pertaining to midday or noon; noonday: as, the meridian sun; the sun's meridian heat or splendor.
2. pertaining to the culmination or highest point or degree (the sun being highest at midday); culminating; highest before a decline: as, athens reached its meridian glory in the age of pericles.
3. pertaining to or marking a geographical north and south line; extending in the are of a great circle passing through the poles: as, a meridian circle on an artificial globe.
4. noting the eighth of professor H. rogers's twelve divisions of the paleozoic series in the Appalachian chain of north america, the names of which suggest metaphorically the different natural periods of the day: it corresponds with the Oriskany sandstone (which see, under sandstone).
5. consummate; complete.
6. midday; noon.
7. midday repose or indulgence; nooning: used specifically as in the quotations.
8. the highest point reached before a decline; the culmination; the point of greatest increment or development.
9. A great circle of a sphere passing through the poles, or the half of such a circle included between the poles; in geography, such a circle drawn upon the earth; in astronomy, such a circle on the celestial sphere.
10. figuratively, the state or condition (in any respect) of the people of one place or region, or of persons in one sphere or plane of existence, as compared with those of or in another: as, the institutions or customs of asia are not suited to the meridian of europe.
11. in ctenophorans, a costa or meridional row of swimming-plates.
12. the meridian from which the meridians bounding townships are measured.

1. a town in eastern mississippi
2. of or happening at noon
3. being at the best stage of development
4. the highest level or degree attainable; the highest stage of development
5. an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator