[ as-troh-fiz-iks ]
/ ˌæs troʊˈfɪz ɪks /
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See synonyms for: astrophysics / astrophysicist on Thesaurus.com

noun (used with a singular verb)
the branch of astronomy that deals with the physical properties of celestial bodies and with the interaction between matter and radiation in the interior of celestial bodies and in interstellar space.
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Origin of astrophysics

First recorded in 1885–90; astro- + physics

OTHER WORDS FROM astrophysics

as·tro·phys·i·cal, adjectiveas·tro·phys·i·cist [as-troh-fiz-uh-sist], /ˌæs troʊˈfɪz ə sɪst/, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use astrophysics in a sentence

British Dictionary definitions for astrophysics

/ (ˌæstrəʊˈfɪzɪks) /

(functioning as singular) the branch of physics concerned with the physical and chemical properties, origin, and evolution of the celestial bodies

Derived forms of astrophysics

astrophysical, adjectiveastrophysicist, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for astrophysics

[ ăs′trō-fĭzĭks ]

The branch of astronomy that deals with the physical and chemical processes that occur in stars, galaxies, and interstellar space. Astrophysics deals with the structure and evolution of stars, the properties of interstellar space and its interactions with systems of stars, and with the structure and dynamics of clusters of stars such as galaxies.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for astrophysics


The branch of astronomy devoted to the study of the physical characteristics and composition of objects in the sky. Typical concerns of astrophysics are how much light the stars give off and the size, mass, and temperature of planets and stars.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.