a. | 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; as, meridian splendor. |
n. | 1. | |
| 1. | Midday; noon. |
| 2. | Hence: The highest point, as of success, prosperity, or the like; culmination. |
| 3. | (Astron.) 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. |
| 4. | (Geog.) 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. |