Word Connections: Sun, Moon, & Stars

R. Philip Bouchard
Mar 21, 2017 · 7 min read

Throughout human history, people have been fascinated with the sun, the moon, and the stars. So it is not surprising that our words for these objects have a long and interesting history. In this episode of Word Connections, we will examine that history, including several surprising connections between English and other languages.

Our modern word “sun” comes from the Old English word sunne, which is quite similar to the modern German word Sonne. English speakers have combined “sun” with many other words to produce a long list of compound words — such as sunshine, sunburn, sunset, sunflower, and Sunday. But this raises the question “Why is Sunday named for the sun?” Ancient Rome, following a tradition it inherited from ancient Greece, named the seven days of the week for the sun, the moon, and the five visible planets in the sky. (The planets took their names from Greek and Roman gods.) This tradition was passed on to many of the languages of Western Europe. For example, Sunday in German is Sonnetag, which literally means “sun day”.

The sunflower got its name because the young flower head always faces the sun — which means that the flower faces east in the morning, and then slowly turns towards the west during the day. During the night it readjusts itself to face east again, in preparation for the sunrise. The flower itself looks like a stylized image of the sun, so the name fits doubly well. Sunflowers are in the genus Helianthus, which literally means “sun flower” — from the Greek words hēlios (sun) and anthos (flower). The element “helium” also gets its name from the Greek hēlios, because the element was originally discovered on the sun, prior to being found on earth. Considering that the discovery was made in 1868, this sounds impossible — but the existence of the element was deduced from details in the spectrum of light that comes from the sun.

The Latin word for sun is sōl (and sōlis). In modern Spanish, which is derived from Latin, the word is still sol. In Italian the word is sole, and in French is it soleil. The Latin word sol has also been adopted into Danish, Norwegian, and Swedish, even though these are not Latin languages. In English, our word “solar” is also derived from the Latin sol.

The English word “moon” comes from the Old English word mōna. Again we see a similar word in German, where the word for moon is Mond. This is remarkably similar to the English word “Monday”, which literally means “moon day”. The German word for Monday is Montag, which also means “moon day”.

Our word “month” is derived from the Old English word mōnath, a direct reference to the moon. Originally the word “month” meant the period of time required for one lunar cycle, which averages 29.5 days. In other words, the time between two consecutive full moons (or between two new moons) is sometimes 29 days and sometimes 30 days.

The Latin word for moon is luna, which is still the word for moon in both Spanish and Italian. The French word lune is quite similar. In English we use the word “lunar” to refer to the moon, as in a lunar eclipse or the “lunar lander” — the vehicle that delivered the astronauts to the moon. We also have the word “lunatic”, derived from the bizarre idea that prolonged exposure to moonlight would cause insanity. And from “lunatic” has come the slang word “loony” to mean crazy.

The English word “star” comes from the Old English steorra. Other Germanic languages have similar words, such as ster in Dutch and Stern in German. More surprising is that the modern Greek word for star is also quite similar — astéri. An older Greek word for star was ástron, from which we get the word “astronomy”, which literally means to define the laws that guide the stars. (Astronomy was originally focused on figuring out the motions of the various objects in the night sky.) The term has broadened to mean the study of all things about the universe beyond the earth. Our word “astronaut” literally means a person who travels to the stars, although none of our astronauts have gone any farther than the moon. The “naut” part of the word, which is also from ancient Greek, means a sailor — and therefore it is the source of our word “nautical”.

The word “astronomical”, which originally meant “pertaining to astronomy”, has undergone an interesting evolution. These days it is common to see the word in a completely different context, such as “an astronomical sum of money”. In this context, the word simply means “an incredibly large number”. (The money is not being used to study the stars.) This new meaning comes from the idea that stars are incredibly numerous and incredibly far away — and therefore we must use incredibly large numbers to talk about them. There are billions of galaxies, each containing billions of stars. The nearest stars are billions of miles away, and the farthest stars are billions of times farther than that. So yes, astronomical numbers can indeed boggle the mind.

In our daily news, the word “star” is quite commonly used to mean a popular figure in entertainment, such as a “movie star”. The obvious comparison is to a brightly shining star in the night sky. Translating this to another language can be a bit tricky. Some languages have borrowed the English word for this purpose, and therefore a movie star in German is a Filmstar. In French, a movie star is a star de cinéma. Certain other languages, such as Spanish, have borrowed the idea, but substituted their own word for “star” — as in estrella de cine.

The word “star” is often used to describe a popular geometric shape that has symmetric radial points. These days, especially in the United States, we have decided that the usual number of rays for a “star” is five — perhaps because of the association with our flag, the “Stars and Stripes”. But the word can also be used for other variations, such as the “Star of David”, which has six points. Of course, a real star has a round shape, without any points. However, it is difficult to discern the precise shape of a star in the night sky with the naked eye — so it is easy to imagine a “star” shape.

We have applied the name of this shape to many living things, such as “starfish” (now often called “sea stars”) and “starfruit”. The word also appears in the names of flowers, such as “Star-of-Bethlehem” and “Yellow Stargrass”. However, the idea is often disguised, occurring in names that come from Latin or Greek roots. The genus Aster — derived from astér, another variation of the Greek word for star — is the name of a genus of daisy-like flowers. The Latin word for star is stella, and this word is even more common in the botanical names of flowers. For example, chickweeds belong to the genus Stellaria, named for the starry shape of the flowers. Another flower, called the Starry Campion, is Silene stellata — where “stellata” literally means “starry” or “star shaped”.

The Italian word for star is stella — unchanged from the Latin. In English we think of this word as a woman’s name. In Spanish the word has evolved into estrella, while in French the word has become étoile. Our English word “constellation”, a grouping of stars in the sky, is clearly derived from stella. On the other hand, the word asteroid is derived from Greek instead of Latin. The “-oid” ending means “similar to”, implying that an asteroid is similar to a star. Actually, an asteroid is much more similar to a planet, but at one time people did not draw much distinction between stars and planets. Our word “asterisk” literally means “little star”, but in this case the word refers to the shape, and not to an object in space.

To the naked eye, the five visible planets look just like bright stars, except that they don’t stay put. Over time, they slowly move from one constellation to another, unlike normal stars. The word “planet” is derived from the Greek phrase planétēs astérēs, which means “wandering star”. The second word of the phrase was eventually dropped, so the word “planet” literally means “wandering”. Other objects in the night sky — not just planets — were often confused with stars. For example, when a meteor passes through the atmosphere at night, producing a brief bright streak across the sky, we call it a “shooting star” or a “falling star”. You can find similar phrases in many other languages. For example, the Swedish stjärnfall and the Dutch vallende ster both literally mean “falling star”.

Certain astronomic terms have become almost universal in modern times. For example, the words “planet”, “comet”, and “meteor” — or words that are nearly identical — are found in virtually all of the languages of Western Europe. However, Icelandic is a fascinating holdout, still using tradition terms in several cases. For example, the word for planet in Icelandic is reikistjarna, which literally means “wandering star”. And the word for comet in Icelandic is halastjarna, which literally means “tail star” — a star with a tail.

Our English word “comet” is also an indirect reference to the tail of a comet. The word derives from the Greek kométēs, which means “wearing long hair”. This word in turn came from the Greek word kómē, which means “hair”. In other words, the ancient Greeks, when looking at a comet, saw a star with long hair instead of a star with a tail. In fact, if you look at photos of several different comets, you will see that the “tail” often bears more resemblance to a full head of hair than it does to an animal’s tail. However, it is unlikely that the term “hairy star” will ever catch on in English.

The word “meteor” has an even stranger origin. It derives from the Greek word metéōron, which means “in the air” — in other words, a meteor is literally “something in the air”. This seems oddly vague. However, it explains another mystery. Have you ever wondered why “meteorology” is the study of the atmosphere and weather, and not the study of meteors? That’s because it also derives from the Greek word metéōron, combined with the suffix “logy”, which means to study something. Therefore the word “meteorology” literally means to study what is happening in the air, which makes perfect sense — certainly more sense than the word “meteor” does!

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The Philipendium

Insightful stories about science, nature, language, and education. Browse a collection of more than 50 fascinating articles.

R. Philip Bouchard

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Writer, educator, and avid student of nature. See more at www.philipbouchard.com

The Philipendium

Insightful stories about science, nature, language, and education. Browse a collection of more than 50 fascinating articles.

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