Meridian, me-rid -e-an, s

a great circle supposed to be drawn so as to pa through the poles of the earth, and the zenith and nadir ofany given place, intersecting the equator at right angles, and dividing the hemisphere into eastern and western [Geog. and Astron.]; midday; noon: the highest point: a. pertaining to the meridian or at mid-day, or to the highest point, or to the magnetic meridian. Magnetic meridian, a great circle, parallel with the direction of the magnetic needle, and pa ing through its poles (L. meridies, mid-day,from medius, the middle,and dies, aday.)