extragalactic

adjective

ex·​tra·​ga·​lac·​tic ˌek-strə-gə-ˈlak-tik 

: originating or existing outside the Milky Way galaxy

also : of or relating to extragalactic space

extragalactic astronomy

Examples of extragalactic in a Sentence

Recent Examples on the Web

Further confirmation of its extragalactic origin came from images taken by the Hubble Space Telescope. —Ashley Strickland, CNN Money, 22 Sep. 2025

That means its origin must be extragalactic, perhaps created in the violence of a star exploding and producing a gamma-ray burst, or a supermassive black hole ripping a star or gas cloud to shreds with its titanic gravitational tidal forces. —Keith Cooper, Space.com, 16 May 2025

This extragalactic neighbor of our home Milky Way galaxy is located almost 200,000 light-years away from Earth and could crash into our home galaxy in about two billion years. —Laura Baisas, Popular Science, 29 Nov. 2023

That’s no supernova The most common extragalactic transient luminous events, meaning flashes of light that evolve and vanish rapidly, are supernovae. —Elizabeth Rayne, Ars Technica, 27 Nov. 2023

Word History

Etymology

International Scientific Vocabulary

First Known Use

1851, in the meaning defined above

Rhymes for extragalactic

• anaphylactic
• intergalactic
• stereotactic
• chemotactic
• chiropractic
• isotactic
• prophylactic
• climactic
• didactic
• galactic
• syntactic
• lactic