Mare Frigoris

Mare Frigoris [fri-gawr-is, -gohr-] noun

1. (Sea of Cold) a dark plain in the northern hemisphere, in the first and second quadrants of the face of the moon: about 55 miles (90 km) wide at its narrowest width and 750 miles (1200 km) long: about 67,000 sq. mi. (174,000 sq. km).