astrophysics

American  

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

noun

(used with a singular verb)

• astrophysics
  plural

1. 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.

---

astrophysics British  

/ ˌæstrəʊˈfɪzɪks /

noun

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

---

astrophysics Scientific  

/ ăs′trō-fĭz′ĭks /

1. 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.

---

astrophysics Cultural  

1. 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.

---

Other Word Forms

Derived Forms

• astrophysicist
  noun
• astrophysical
  adjective

Inflected Forms

Nouns

• astrophysics
  plural

Etymology

Origin of astrophysics

First recorded in 1885–90; astro- + physics

Explanation

Astrophysics is the study of stars and other objects in space, and the way they move and change over time. If you're fascinated with black holes, you may want to go into astrophysics. Complicated subjects like galaxy formation, the possibility of time travel, and the way the solar system has evolved are all included in the branch of astronomy known as astrophysics. When you study astrophysics, you apply the concepts and theories of physics to astronomic observations. Astrophysicist came first, from the Greek aster, or "star," and ta physika, "the natural things," or "natural science."

Example Sentences

See Examples For:

astrophysics

"We've recently been really focused on astrophysics of the explosions and how they impact cosmology," he said.

From Science Daily ● Aug. 29, 2026

As a member of NASA’s class of “flagship” astrophysics missions, its acclaimed colleagues include the Hubble and the James Webb space telescopes.

From Los Angeles Times ● Aug. 28, 2026

"This immense energy makes cosmic rays important in astronomy and astrophysics," said first and corresponding author of the study Tsunefumi Mizuno, associate professor at Hiroshima University's Hiroshima Astrophysical Science Center.

From Science Daily ● Aug. 2, 2026

"This is a lot of firsts stacked on top of each other," said Shawn Domagal-Goldman, the director of NASA's astrophysics division, during a recent call with reporters.

From Barron's ● Jun. 30, 2026

Probably my favorite thing, other than joking around with my team, was when an astrophysics grad student from the University of Central Florida came to speak.

From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas