galaxy

noun

gal·​axy ˈga-lək-sē 

plural galaxies

1

a

often Galaxy : milky way galaxy

—used with the

b

: any of the very large groups of stars and associated matter that are found throughout the universe

2

a

: an assemblage of brilliant or notable persons or things

a galaxy of artists

b

: world sense 11

… remained galaxies apart on the issue …

—Newsweek

Did you know?

The system of stars that includes our sun looks, in the night sky, like a broad band of light. We call this band the Milky Way. The idea of the whiteness of the Milky Way being similar to that of milk is much older than the English language, however. Galaxias, the Greek word for the Milky Way, was derived from the Greek gala, “milk.” English galaxy, derived from Greek galaxias, was not used until the 19th century as a generic term for other star systems as well as the one in which we live.

Synonyms of galaxy

• world

Examples of galaxy in a Sentence

The event was attended by a galaxy of artists.

they're a galaxy apart when it comes to politics

Recent Examples on the Web

Also like the natural world, the Tyranids are patient, slowly devouring the edges of the galaxy and reproducing in unthinkable numbers in the darkness of space. —Alan Bradley, Space.com, 8 Nov. 2025

The source of the flare is an active galactic nucleus, or AGN — a bright, compact region at the center of a galaxy — and it’s powered by a supermassive black hole that is actively feeding on material. —Ashley Strickland, CNN Money, 7 Nov. 2025

The hypothesis was based on the taking of distance measurements to faraway galaxies using type 1a supernovae, stellar explosions that occur in twin star systems where one of the stars is a white dwarf. —Ian Randall, MSNBC Newsweek, 6 Nov. 2025

It was also tilted with respect to the plane of the galaxy. —Phil Plait, Scientific American, 6 Nov. 2025

Word History

Etymology

Middle English galaxias, galaxie, borrowed from Late Latin galaxias, borrowed from Greek galaxías (probably originally conjoined with kýklos "wheel"), from galakt-, stem of gála "milk" (going back to Indo-European *glkt-, attested elsewhere only in Latin lact-, lac "milk," Armenian kat'n) + -ias, noun suffix, especially of natural phenomena

First Known Use

15th century, in the meaning defined at sense 1a

Phrases Containing galaxy

• elliptical galaxy
• Milky Way galaxy
• radio galaxy
• satellite galaxy
• Seyfert galaxy
• spiral galaxy

Kids Definition

galaxy

noun

gal·​axy ˈgal-ək-sē 

plural galaxies

1

: milky way galaxy

2

: one of the very large groups of stars and other matter that are found throughout the universe

Etymology

Middle English galaxie "the Milky Way," from Latin galaxias (same meaning), from Greek galaxias "Milky Way," from galakt-, gala "milk"