- Being at, or pertaining to, midday; belonging to, or passing through, the highest point attained by the sun in his diurnal course." Meridianhour." [Milton.]"Tables . . . to find the altitude meridian." [Chaucer.]
- Pertaining to the highest point or culmination; as, meridian splendor.
Etymology: F. méridien, L. meridianus pertaining to noon, fr. meridies noon, midday, for older medidies; medius mid, middle + dies day. See Mid, and Diurnal