1. Either of the two points on the sun's apparent annual path where it is displaced farthest, north or south, from the earth's equator, that is, a point of greatest deviation of the ecliptic from the celestial equator. The Tropic of Cancer (north) and Tropic of Capricorn (south) are defined as those parallels of latitude that lie directly beneath a solstice. 2. Popularly, the time at which the sun is farthest north or south; the “time of the solstice. ”

In the Northern Hemisphere the summer solstice falls on or about 21 June, and the winter solstice on or about 22 December. The reverse is true in southern latitudes. Compare equinox.