What does galaxy mean?
A galaxy is an immense, gravitationally bound system comprising stars, stellar remnants, interstellar gas and dust, and dark matter; the largest contain trillions of stars. Our own galaxy, the Milky Way, is just one among hundreds of billions in the observable universe. The word carries a striking history: it derives from the Greek galaxias kyklos, the 'milky circle', a poetic description of the hazy band of light that arcs across the night sky, which ancient observers likened to spilled milk. Beyond astronomy, galaxy has a well-established figurative sense, describing a dazzling gathering of notable people or things — critics might speak of 'a galaxy of talent' at a festival or 'a galaxy of ideas' in a body of work. This figurative use lends the word a connotation of brilliance and abundance, making it equally at home in scientific writing and elegant prose.
A massive system of stars, gas, dust, and dark matter held together by gravity, of which the Milky Way is one example.
"The Andromeda galaxy is the nearest major galaxy to our own."
In strict astronomical usage, 'galaxy' names any such system, including our own.
An impressive or illustrious collection of people or things.
"The conference attracted a galaxy of leading scientists from around the world."
This figurative sense is common in journalism and literary writing and carries a positive connotation.
The plural follows the standard -y to -ies pattern for nouns ending in a consonant plus y.
"Modern telescopes have revealed countless galaxies beyond our own."
"Galaxy" comes from the Greek gala, meaning milk — because the hazy band of the Milky Way looked like spilled milk across the night sky.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of galaxy
The word galaxy derives from the Greek galaxias (kyklos), meaning 'milky (circle)', rooted in gala, 'milk'. Ancient Greek writers used the term to describe the luminous band we now call the Milky Way, whose pale glow was mythologized as milk spilled by the goddess Hera. The term passed into Latin and entered English in the early modern period, initially referring specifically to the Milky Way before astronomers recognized other such systems. It shares its milk-derived root with words such as lactic, lactose, and latte, all ultimately tracing back to the same Greek noun.
Related word forms
How galaxy is actually used
The astronomical sense is neutral and technical; the figurative sense ('a galaxy of talent') is somewhat literary or journalistic in register and connotes admiration. The plural 'galaxies' is standard in both senses.
Easily confused with galaxy
A constellation is an apparent pattern of stars seen from Earth within our own galaxy, whereas a galaxy is an enormous gravitationally bound system containing billions of stars.