A circle of constant longitude passing through a given place on the earth's surface and the terrestrial poles. The prime meridian is the meridian at which the longitude is defined to be 0°.
A point or period of highest development, greatest prosperity, or the like. The civilization reached its meridian during the reign of the wise king.
In traditional Chinese medicine, a pathway in the body along which vital energy is said to flow. Acupuncturists believe that stimulating points along the meridians can restore balance to the body.
The bell tolled at meridian to mark the start of the lunch hour.
In astronomy, an imaginary great circle on the celestial sphere that passes through the celestial poles and the observer's zenith. When the star crossed the local meridian, the observer recorded its highest altitude.