Thursday of this week marks the autumnal equinox. Autumnus in Latin word names the fall season we’re about to enter. Equinox combines two Latin words: the adjective aequus, which means “equal,” and the noun nox, which means “night.” As you know, this day is one of two during the year when the day, that is, sunrise to sunset, is of the same duration as the night, that is, sunset to sunrise. The night is equal to the day. From this Thursday on, the days will grow shorter until the winter solstice, December 21, when the days gradually begin to become longer.
The earth’s tilt on its axis explains this phenomenon. No one will know if you have to review how that works here.
A few weeks ago, Sarah suggested we examine the word day and related words, and this week seemed like a good time, what with equinoxes and nights and days and all.
Our word day and the Latin dies are not related. I know, right? Hard to believe, isn’t it? Day comes from an Old English root, whereas dies is thought to derive from the Indo-European *dyeu, meaning “to shine.”
Even more interesting are all the words springing from dies and its Indo-European root. I remember being surprised and impressed when a professor pointed out to us students the similarities among deus (god), Zeus, divine, deity, adieu, diva, and many others. Primitive people have the good sense to honor the sun, the thing that shines, because we depend on it for life. So, all those divine words have etymological connections to dies, the Latin word for “day.” In a more mundane sense, you encounter the Latin dies in phrases like “per diem”(by the day) and in Horace’s admonition “Carpe diem” (Seize the day). (That case ending “m” makes the word an object.)
Diet, the regimen that limits your daily calories, comes from Greek diaita, meaning “a way of life,” not the Latin dies. But linguists do link diet, as in the Diet of Worms in 1521, the big meeting which condemned Martin Luther, to both diaita and dies. Very confusing. Here’s a source, so you can study up yourself. Be prepared for a quiz.