black hole

[ blak-hohl ]
See synonyms for black hole on Thesaurus.com
noun
  1. Astronomy. a theoretical massive object, formed at the beginning of the universe or by the gravitational collapse of a star exploding as a supernova, whose gravitational field is so intense that no electromagnetic radiation can escape.

  2. a deep, immeasurable space into which people or things vanish; an abyss: I use earphones every day, but hate digging around for them in my black hole of a purse.

Origin of black hole

1
First recorded in 1940–45 for def. 2; 1960–65 for def. 1

Other definitions for Black Hole (2 of 2)

Black Hole
[ blak-hohl ]

noun
  1. Also called Black Hole of Cal·cut·ta [blak-hohluhv kal-kuht-uh] /ˈblæk ˈhoʊl əv kælˈkʌt ə/ . a small prison cell in Fort William, Calcutta, in which, in 1756, Indians are said to have imprisoned 146 Europeans, only 23 of whom were alive the following morning.

  2. (lowercase) any usually wretched place of imprisonment or confinement.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use black hole in a sentence

  • These black holes are a type known as quasars: extremely massive objects that emit more light than the rest of the galaxy.

    The Black Hole Tango | Matthew R. Francis | November 24, 2014 | THE DAILY BEAST
  • The observable Universe contains around 100 billion large galaxies and a comparable number of supermassive black holes.

    The Black Hole Tango | Matthew R. Francis | November 24, 2014 | THE DAILY BEAST
  • The growth of black holes and galaxies are linked, though the details are still sketchy in places.

    The Black Hole Tango | Matthew R. Francis | November 24, 2014 | THE DAILY BEAST
  • That leads us to wonder why galaxies and their black holes somehow “know” where they are in the cosmic web.

    The Black Hole Tango | Matthew R. Francis | November 24, 2014 | THE DAILY BEAST
  • Now, a new observation seems to show that black holes also behave according to their place in the cosmic web.

    The Black Hole Tango | Matthew R. Francis | November 24, 2014 | THE DAILY BEAST
  • In the walls of the ravines black holes gaped, for caves 303 were almost as numerous as springs.

    A Virginia Scout | Hugh Pendexter
  • The black-hole of that ship warn't a strong one, to a judge of black-holes that could swim and dive.

    Great Expectations | Charles Dickens
  • If we found that it made a regular trail, and led to one of these same black holes, we'd know more than we do right now.

  • His small eyes were sunk deep in his head, showing like black holes in the heavy, flat, hairless face.

  • There were scores of just similar ragged black holes among the tumbled rocks of the great wall.

British Dictionary definitions for black hole

black hole

/ astronomy /


noun
  1. an object in space so dense that its escape velocity exceeds the speed of light

  2. any place regarded as resembling a black hole in that items or information entering it cannot be retrieved

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

Scientific definitions for black hole

black hole

  1. An extremely dense celestial object whose gravitational field is so strong that not even light can escape from its vicinity. Black holes are believed to form in the aftermath of a supernova with the collapse of the star's core. See also event horizon. See more at star.

a closer look

When a very massive star ends its life in a supernova explosion, the remaining matter collapses in upon itself. If there is enough mass in this collapsed star, it becomes a black hole. A black hole is so dense that its gravitational forces are strong enough to prevent anything that comes close enough to the region known as the event horizon from escaping. Even light cannot escape, since the escape velocity (the velocity needed for an object to escape some larger object's gravitational field) necessary to escape a black hole is greater than the speed of light. Black holes are extremely dense: for the Sun, which has a diameter of about 1,390,000 kilometers (862,000 miles), to be as dense as a black hole, its entire mass would have to be squeezed down to a ball fewer than 3 kilometers (5 miles) across. Some theorists postulate that the material in a black hole may be compressed to a single point of infinite density called a singularity. Because astronomers cannot directly observe a black hole, they infer its existence from the effects of its gravitational pull. For example, when a black hole results from the collapse of one star in a binary star system, it attracts material from the remaining star. This material forms an accretion disk, which compresses and heats up until it emits detectable x-rays. Black holes are thought to reside in the centers of many galaxies, including our own Milky Way.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for black hole

black hole

In astronomy, an object so massive that nothing, not even light, can escape its gravitation. Black holes were given their name because they absorb all the light that falls on them. The existence of black holes was first predicted by the general theory of relativity. Supermassive black holes have been found in the centers of many galaxies. Stellar black holes are thought to arise from the death of very massive stars. Astronomers expect to find many stellar black holes in the Milky Way.

Notes for black hole

Figuratively, the term black hole is used to refer to a total disappearance: “They never saw the man again — he might as well have fallen into a black hole.”

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.

Other Idioms and Phrases with black hole

black hole

A wretched prison cell or other place of confinement. For example, The punishment is solitary confinement, known as the black hole. This term acquired its meaning in 1756 with the event known as the Black Hole of Calcutta. On the night of June 20, the ruler of Bengal confined 146 Europeans in a prison space of only 14 by 18 feet. By morning all but 23 of them had suffocated to death. Although historians since have questioned the truth of the story, it survives in this usage.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.