galaxy

noun

gal·​axy ˈga-lək-sē 

plural galaxies

1

a

often capitalized : 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

• light-year
• 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

Here's what to know about how the powerful forces may have shaped galaxies and how the discovery may help astronomers better study black holes. —Eric Lagatta, USA Today, 6 June 2025

However, this design allows for more light transfer through the lens, helping keen astronomers to see distant planets and galaxies. —Matt Morris, Space.com, 6 June 2025

The way dark matter and stars interact influences how galaxies change over time. —Stephen Clark – Jun 6, ArsTechnica, 6 June 2025

Galactic impact update For more than 100 years, a collision between the Milky Way galaxy and its largest neighbor, the Andromeda galaxy, was predicted to occur in about 4.5 billion years. —Jade Walker, CNN Money, 4 June 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"