Meridian
Webster's Dictionary [1]
(1):
(a.) Midday; noon.
(2):
(a.) Pertaining to the highest point or culmination; as, meridian splendor.
(3):
(a.) Being at, or pertaining to, midday; belonging to, or passing through, the highest point attained by the sun in his diurnal course.
(4):
(a.) Hence: The highest point, as of success, prosperity, or the like; culmination.
(5):
(a.) 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.) 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.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]
is the technical term for the siesta or noon-day sleep in a convent, allowed to be taken during one hour after hall-time.
The Nuttall Encyclopedia [3]
An imaginary great circle passing through the poles at right angles to the equator.