black hole

Pluralblack holes

Formsblack holes, black holing, black holed

1. 1
   gravity trap (space)nouncountable

   A region of spacetime whose gravitational pull is so strong that no matter or energy, not even light, can escape from it.

   Astronomers detected X-rays from gas being pulled into a black hole at the heart of the galaxy.

   When a very massive star collapses at the end of its life, it can become a black hole.

   Note

   The astronomical name has a traceable origin. Hong-Yee Chiu credited it to his colleague Robert H. Dicke, who around 1960–1961 likened these objects to the Black Hole of Calcutta, a lockup in the older, punitive meaning and a place that lets nothing out. Strictly a region of spacetime, a black hole is still talked about as an object, from Dicke's remark to Hannah Devlin's 2019 report in The Guardian on the first image of one.

2. 2
   voidnounfigurativelycountable

   A void into which things vanish for good, or an area or subject that is impossible to see into or understand.

   That committee is a black hole: proposals go in and nobody ever hears about them again.

   The decade before the census is a black hole in the town's history, with almost no records surviving.

   Similarvoid, blank

   Note

   In figurative use the phrase often comes with a word saying where the void is: an internet black hole, a black hole in the data. People fall down one, as Jenifer Hanen did on Black Phoebe in 2004. The other half, a place no one can see into, gives Tom Zeller Jr.'s 2006 headline The Internet Black Hole That Is North Korea, where censorship cuts a country off. Both halves echo the astronomical object.

3. 3
   punishment cellnouncountable

   A place where someone is confined as a punishment, such as a cell, a lockup, or a military guardroom.

   The sergeant ordered the drunken private confined to the black hole until morning.

   Boys who talked back to the schoolmaster were shut in the black hole for the afternoon.

   Similarcell, lockup, guardroom

   Note

   Long before astronomy took up the phrase, it belonged to the barracks and the schoolroom. Herbert Spencer's Education (1860) sets the black hole beside rods and ferules, and The Rifle Brigade Chronicle for 1897 writes it black-hole, noting that the Articles of War capped a soldier's stay there at eight days without a court-martial. It usually comes with the definite article: clapped into the black hole for the night.

4. 4
   data sink (network)nouncountablebefore a noun

   A place on a network where incoming traffic is silently discarded instead of being delivered.

   The provider routed traffic from the attacking addresses into a black hole, so the flood of requests never reached the site.

   Our mail server checks every sender against a black hole list before accepting a message.

   Note

   Silence is what defines a black hole on a network. Traffic sent into one is dropped with no reply at all, so the sender learns nothing, not even that it was refused. The phrase often stands before another noun, and there it may close up into one word: spam is fought with a blackhole list kept on a blackhole server.

5. 5
   drop trafficverbtransitive

   To redirect network traffic or similar data so that it goes nowhere, or to discard incoming traffic.

   We asked our upstream provider to black hole the attacked prefix until the flood died down.

   The mail server black holes messages from known spam sources instead of bouncing them back.

   Similardiscard, drop

   Note

   The verb can take either end of the journey as its object: engineers black hole a flood of packets, but they also black hole the attacked prefix itself. That second use is a deliberate sacrifice, cutting the target off so the rest of the network keeps running. The past forms turn up both open, as black holed, and closed up, as blackholed, matching the one-word spelling of the network noun.

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