Definition of "accretion disk" [accretion disk]

• A disk of interstellar material surrounding a celestial object with an intense gravitational field, such as a black hole. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In four hours of drifting through the accretion disk they'd spotted, identified, and filmed no fewer than fifteen different variants of space-going creatures."