[ as-troh-fiz-iks ]
/ ˌæs troʊˈfɪz ɪks /

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.

Nearby words

  1. astronomical year,
  2. astronomy,
  3. astrophotography,
  4. astrophotometry,
  5. astrophysicist,
  6. astrosphere,
  7. astrotourist,
  8. astroturf,
  9. astroturfing,
  10. asturian

Origin of astrophysics

First recorded in 1885–90; astro- + physics

Related formsas·tro·phys·i·cal, adjectiveas·tro·phys·i·cist [as-troh-fiz-uh-sist] /ˌæs troʊˈfɪz ə sɪst/, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for astrophysicist

British Dictionary definitions for astrophysicist


/ (ˌæstrəʊˈfɪzɪks) /


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

Word Origin and History for astrophysicist



1869, usually hyphenated at first, from astro- + physicist. Astrophysics is recorded from 1877.

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for astrophysicist


[ 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.

Culture definitions for astrophysicist


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.