fault line

American  

noun

Geology.

• fault lines
  plural

1. the intersection of a fault with the surface of the earth or other plane of reference.

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fault line British  

noun

1. Also called: fault plane.  geology the surface of a fault fracture along which the rocks have been displaced

2. a potentially disruptive division or area of contention

   Europe remains the main fault line in the Tory Party

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Other Word Forms

Noun Inflected Forms

• fault lines
  plural

Etymology

Origin of fault line

First recorded in 1865–70

Example Sentences

See Examples For:

fault line

Playing a childless, vain, pitch-perfect vision of Los Angeles’ wickedness in “Maps to the Stars,” Julianne Moore mothered so hard she almost separated California right down the San Andreas fault line.

From Salon ● May 10, 2026

In Moerdijk, that dilemma is no longer abstract; it's immediate, and it is set to reshape the lives of Jaco, Andrea, Jacques and everyone living on the fault line of the green transition.

From BBC ● Apr. 12, 2026

The episode exposed a fault line in Silicon Valley between engineers who viewed autonomous targeting as an ethical red line and defense officials who saw it as essential.

From Barron's ● Apr. 5, 2026

He astutely flags “medical gatekeeping” as an emerging fault line.

From The Wall Street Journal ● Feb. 8, 2026

The massacres had happened over two hundred years ago, but the wound they’d made in our cultural history was left raw and festering, like a fault line that may begin trembling again at any moment.

From "The City Beautiful" by Aden Polydoros

Related Words

• rift