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 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 fault line exposed now is that private credit is being offered to retail investors and wealthy individuals whose liquidity preferences are different from sophisticated, more patient institutional investors.

From MarketWatch ● Feb. 26, 2026

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

From The Wall Street Journal ● Feb. 8, 2026

You don’t know that when a memo arrives to confirm the assignment, some deep and unseen fault line in your life has begun to tremble, that some hold is already starting to slip.

From "Becoming" by Michelle Obama

Related Words

• rift