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

Beginning in February 2024, the team began a six-year project called the Euclid Wide Survey, with the aim of mapping a swath of extragalactic space. — Adam Kovac, Scientific American, 7 July 2026

Additionally, as neutrino creation is accompanied by gamma-ray emission, the model had to ensure that in creating high-energy neutrinos, blazars didn't generate enough gamma-ray radiation to exceed the extragalactic gamma-ray background measured by the Fermi space telescope. — Robert Lea, Space.com, 28 May 2026

In the slant, Shao sees evidence for an extraterrestrial, even extragalactic origin for lightning — a cosmic-ray shower. — Quanta Magazine, 6 May 2026

Its First Look observations, released in June of 2025, resulted in the discovery of more than 2000 new asteroids, as well as revealing a wealth of data about extragalactic objects. — Big Think, 4 Nov. 2025

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