- Astronomy.
- 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.
- either of the two points in the ecliptic farthest from the equator.
- a furthest or culminating point; a turning point.
- either the shortest day of the year (winter solstice) or the longest day of the year (summer solstice)
- either of the two points on the ecliptic at which the sun is overhead at the tropic of Cancer or Capricorn at the summer and winter solstices
