The term "solstice" refers to two specific times of the year when the sun reaches its highest or lowest point in the sky at noon, resulting in the longest day or the longest night. These events occur twice a year: the summer solstice, around June 21, when the day is longest, and the winter solstice, around December 21, when the night is longest.
The word "solstice" comes from the Latin "solstitium," which is a combination of "sol" meaning "sun" and "stitium," which is derived from "sistere" meaning "to stand still." This relates to the perception that the sun appears to stand still in its path during these times.