Definition of meridian

• the highest level or degree attainable; the highest stage of development; "his landscapes were deemed the acme of beauty"; "the artists gifts are at their acme"; "at the height of her career"; "the peak of perfection"; "summer was at its peak"; "...catapulted Einstein to the pinnacle of fame"; "the summit of his ambition"; "so many highest superlatives achieved by man"; "at the top of his profession"
• a town in eastern Mississippi
• an imaginary great circle on the surface of the earth passing through the north and south poles at right angles to the equator; "all points on the same meridian have the same longitude"