as·​tro·​phys·​ics ˌa-strə-ˈfi-ziks How to pronounce astrophysics (audio)
plural in form but singular or plural in construction
: a branch of astronomy dealing especially with the behavior, physical properties, and dynamic processes of celestial objects and phenomena
astrophysical adjective
astrophysically adverb
astrophysicist noun

Examples of astrophysics in a Sentence

Recent Examples on the Web Prior to tech, Mandal was an astrophysics researcher at NASA and Stanford University. Fortune Editors, Fortune, 27 July 2022 Scientists perform research there examining climate systems, astrophysics, biology and other fields of science. Joseph De Avila, WSJ, 7 Nov. 2022 The panel members, who began their work last week, include leaders in the fields of astrophysics, data science, biological oceanography and electrical engineering, as well as a former astronaut. Deborah Netburnstaff Writer, Los Angeles Times, 2 Nov. 2022 Chaos theory explains how complex systems work in multiple fields, including astrophysics, climate change, and neuroscience. Sarah Wells, Popular Mechanics, 22 Sep. 2022 The Kavli Prize honors scientists for breakthroughs in astrophysics, nanoscience, and neuroscience — transforming our understanding of the big, the small and the complex. Scientific American Custom Media, Scientific American, 29 July 2022 Overall, astrophysics, Earth science, and Heliophysics (Sun studies) did OK. Phil Plait, Discover Magazine, 13 Feb. 2012 Nine months ago, the doctor in astrophysics was hunting asteroids at California Institute of Technology’s Palomar Observatory when assisted artificial intelligence flagged an unknown comet. Carlos R. Muñoz,, 10 Jan. 2023 Emma Chapman is an award-winning Royal Society Research Fellow in astrophysics, based at Imperial College London. Emma Chapman, Discover Magazine, 6 Mar. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'astrophysics.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


astro- + physics, probably after German Astrophysik

Note: The term Astrophysik was introduced by the German physicist Johann Karl Friedrich Zöllner (1834-82) in Photometrische Untersuchungen (Leipzig, 1865), pp. 315-16: "Sowohl die heutige Entwicklungsphase der Astronomie als auch das täglich sich steigernde Interesse für die Anwendung rein physikalischer Methode auf astronomische Objecte, scheinen anzudeuten, dass bereits gegenwärtig alle Elemente zur Bildung jenes neuen Theils der Astronomie vorhanden sind. Derselbe dürften vielleicht nicht unpassend mit dem Namen 'Astrophysik' belegt werden, zum Unterschiede von dem bisher in Deutschland allgemein als 'physische Astronomie' bezeichnete Theile.' ("Both the current phase of the development of astronomy and the interest, rising daily, in the applying purely the methods of physics to astronomical objects seem to indicate that all the elements for forming that new branch of astronomy are presently already at hand. This branch should perhaps not unsuitably be given the name 'astrophysics,' to distinguish it from the branches generally characterized up to now as 'physical astronomy' in Germany.")

First Known Use

1870, in the meaning defined above

Time Traveler
The first known use of astrophysics was in 1870

Dictionary Entries Near astrophysics

Cite this Entry

“Astrophysics.” Dictionary, Merriam-Webster, Accessed 28 May. 2024.

Kids Definition


as·​tro·​phys·​ics ˌas-trə-ˈfiz-iks How to pronounce astrophysics (audio)
: a branch of astronomy dealing with the physical and chemical measurements of the heavenly bodies
astrophysical adjective
astrophysicist noun
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