Solstice: The word means "sun stop." It refers to the two moments each year when the sun appears to be farthest from the equator. On the winter solstice in our hemisphere (around December 22), the sun seems to reach its most southerly point. It is our shortest day of the year. From there, it seems to head north until it reaches its most northerly point. That is our summer solstice (around June 21): the longest day of the year. When the Northern Hemisphere has its summer solstice, the Southern Hemisphere has its winter solstice, and vice versa.

The sun doesn't really move, but it looks like it does to us. That's because our Earth is tilted as it revolves around the sun once a year.

Winter Solstice in the Northern Hemisphere

Summer Solstice in the Northern Hemisphere