accretion disk

noun

variants or less commonly accretion disc

plural accretion disks also accretion discs

: a disk of usually gaseous matter surrounding a massive celestial object (such as a black hole) in which the matter gradually spirals in toward and accretes onto the object as a result of gravitational attraction

Evans' team studied a supermassive black hole with jets 800 million light-years away named 3C 33. They never found an expected X-ray pattern … which results from light reflecting off the accretion disk.

—Bill Andrews

Most other moons are either captured planetesimals, or they formed along with the planet in a common accretion disc.

—Daniel Herwartz, et al.

Examples of accretion disk in a Sentence

Recent Examples on the Web

Rotating black holes Some black holes, however, rotate in a different direction than the accretion disk around them. —David Garofalo, The Conversation, 31 Mar. 2025

These are supermassive black holes with masses millions or billions of times that of the sun, surrounded by a flattened cloud of swirling gas and dust called an accretion disk. —Robert Lea, Space.com, 8 Apr. 2025

The plasma that makes up the accretion disk comes from farther out in the galaxy. —David Garofalo, The Conversation, 31 Mar. 2025

Then, in 2023, the accretion disk cooled back down again, resulting in the dimming, although matter continues to flow from the disk to the white dwarf at a slower rate. —Keith Cooper, Space.com, 26 Mar. 2025

Word History

First Known Use

1972, in the meaning defined above

Rhymes for accretion disk

• videodisc
• basilisk
• bisque
• brisk
• disc
• fisc
• fisk
• frisk
• risk
• whisk