Noun: Solstice (SOHL-stis)
Definition: Either of the two times a year when the sun is at its greatest distance from the celestial equator: about June 21, when the sun reaches its northernmost point on the celestial sphere, or about December 22, when it reaches its southernmost point.
Sample sentence: Many Scandinavians celebrate the summer solstice with a big festival of music, dancing and bonfires.