Today marks the first day of fall, which coincides with the autumnal equinox in the Northern Hemisphere. In the Southern Hemisphere, it’s spring (vernal) equinox.
So why are they called fall and spring and how did the four seasons get their names?
The origin of fall isn’t quite clear, but several sources think it came from leaves falling from trees. Mentalfloss.com reports that it surfaced as a season’s name in late-16th century England and became popular during the 17th century. At that point, the name was carried over to North America. Autumn, another name for the fall season, stems from the Old French word autompne from the Latin autumnus and is preferred over fall in Great Britain.
The English first called the season autumn in the 12th century, though it was rare until about 200 years later. Then in the 16th century, it became popular and the words fall and autumn were often used interchangeably. Before either, the season was referred to as harvest.
Winter originates from the Proto-Germanic word wentruz, which probably derives from the Proto-Indo-European wed, meaning wet. Some think it came from the Proto-Indo-European wind, meaning white. Another source reports winter stems from an old Germanic word meaning “time of water” and refers to rain and snow along with cold temperatures.
Before the word spring sprung, it was referred to as Lent in Old English. During the 14th century, springing time was coined from plants springing from the ground. A century later, the phrase was shortened to spring-time and then in the 16th century, just spring.
Summer comes from the Old English name for that time of year, sumor. This derives from the Proto-Germanic sumar-, which came from the Proto-Indo-European root sam-. Sam-, a variant of sem-, means together/one.
And by the way, if you wonder about equinox, there are two each year. In the Northern Hemisphere, autumnal comes in September and vernal in March and vice versa in the Southern Hemisphere. On these days, which occur on or near March 20 or 21 and Sept. 22, the sun shines directly on the equator and the length of day and night are nearly—but not exactly—equal.
Sources: Mentalfloss.com, Barnhart Concise Dictionary of Etymology and Todayifoundit.com.