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• crux
  crux

  noun

  a vital, basic, decisive, or pivotal point.
• Crux
  Crux

  noun

  Southern Cross.

crux

¹ American  

[kruhks] / krʌks /

noun

plural

cruxes, cruces

1. a vital, basic, decisive, or pivotal point.

   The crux of the trial was his whereabouts at the time of the murder.

   Synonyms:

   gist, core, heart, essence

2. a cross.

3. something that torments by its puzzling nature; a perplexing difficulty.

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Crux ² American  

[kruhks] / krʌks /

noun

Astronomy.

genitive

Crucis

1. Southern Cross.

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crux ¹ British  

/ krʌks /

noun

1. a vital or decisive stage, point, etc (often in the phrase the crux of the matter )

2. a baffling problem or difficulty

3. mountaineering the most difficult and often decisive part of a climb or pitch

4. a rare word for cross

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Crux ² British  

/ krʌks /

noun

1. the more formal name for the Southern Cross

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Etymology

Origin of crux¹

1635–45; < Latin: stake, scaffold, or cross used in executions, torment; figurative senses perhaps < New Latin crux ( interpretum ) (commentators') torment, a difficult passage in a text; cf. crucial

Origin of Crux²

< Latin: a cross

Explanation

The essential point or problem is the crux. People are always trying to get to the crux of a matter or the crux of a problem, while others try to distract them. The noun crux is often followed by the phrases "of the matter" or "of the problem." When people are trying to identify the crux of something, it's like they want to get to the heart of it. They want to peel back the layers and find out what something is really all about or what is causing the problem. No more beating around the bush!

Example Sentences

The crux of Brockman's testimony so far has been that Musk was aware of plans to shift OpenAI to be more of a traditional for-profit business.

From BBC • May 5, 2026

“Crucially, we also believe we are at the crux of a gross margin inflection point, driven by improving utilizations and GlobalFoundries aggressively expanding into accretive end-markets,” Muse wrote.

From Barron's • May 4, 2026

The crux of the outrage surrounding Fennell’s film stemmed largely from the fact that she refused to rename her relatively loose, aesthetic-minded adaptation with a title that didn’t directly reference Emily Brontë’s novel.

From Salon • May 3, 2026

But the crux will be, who broke the laws?

From Slate • Apr. 20, 2026

That’s the reality of getting old, and I guess that’s really the crux of the matter.

From "Water for Elephants" by Sara Gruen

Related Words

• bottom line
• core
• essence
• gist
• nub