The far-out etymologies of celestial bodies

Wordymology is a series in which the editors at The Free Dictionary explore the origins of the names of things.
When it comes to their names, the cast of characters in the nighttime sky is much stranger than you might think.


The word “planet” has its roots in the Greek words planāsthai, meaning “to wander,” and planētēs, meaning “wanderer.” The ancient Greeks likely used this name because they observed the planets moving, unlike other celestial objects.
The wandering planets have elliptical orbits, which means that they revolve around the Sun in a path shaped like an oval, not a circle. The word “elliptical” comes from the Greek word elleiptikos, meaning “defective.” Elleiptikos, in turn, comes from the Greek word elleipsis, which means “a falling short.”

Armed Guards

You might know that a satellite is any celestial body or artificial instrument that orbits a planet. But did you know that “satellite” comes from the Latin word satelles, meaning “attendant” or “armed guard”? The Latin term probably has its roots in an Etruscan word meaning “one who carries or strikes with an axe.”

Long-Haired Stars

A comet is essentially a body of ice and rock with a long, glowing vapor tail. The comet’s appearance was fancifully captured by the ancient Greeks when they named it komētēs, meaning “wearing long hair.” (Komē is the Greek word for “hair.”)

All Stars

Constellations are made up of stars—both literally and etymologically. The word gets its name from the Late Latin constellātiō, which combines the Latin words for “together” (com-) and “star” (stella).

Kinda Stars

A “quasar” is an extremely bright, star-like object. Its name comes from an abbreviation of “quasi-stellar,” highlighting its star-like quality.

Pulsating Stars

The term “quasar” influenced the name of the pulsar, which also emphasizes its very nature. “Pulsar” is an abbreviation for “pulsating star,” referring to how it rotates very quickly and releases pulses of radiation.

Star Sailors

The word “astronaut” is, ultimately, a combination of two Greek words: astron, meaning “star,” and nautēs, meaning “sailor.” You might also recognize nautēs as the basis for the English word “nautical.”

A Galaxy So Nice, They Named It Twice

The Milky Way Galaxy was so named because it appears (if conditions are dark enough) as a white band across the night sky.
But its name is a bit redundant, considering the precursor to the word “galaxy”—the Latin galaxias—was used to refer to the Milky Way. Not to mention that it derives from gala, the Greek word for “milk.” “Galaxy” is also related to the Latin word for “milk,” lac (seen in the word “lactose” and others).

A Star System So Famed, It Was Never Named

Despite humans’ affinity for naming things, the proper name of our home solar system is simply “the Solar System.” What do you think it should be called?
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