unless

American  

[uhn-les, uhn-] / ʌnˈlɛs, ən- /

conjunction

1. except under the circumstances that.

   I'll be there at nine, unless the train is late.

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preposition

1. except; but; save.

   Nothing will come of it, unless disaster.

unless British  

/ ʌnˈlɛs /

conjunction

1. (subordinating) except under the circumstances that; except on the condition that

   they'll sell it unless he hears otherwise

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preposition

1. rare except

Etymology

Origin of unless

1400–50; late ME prepositional phrase on less (also o less(e) , earlier upon less ) on a lesser footing or condition (than); first used as a preposition and conjunction in the early 16th century; see on, less

Example Sentences

Unless a mayoral candidate secures a majority of the vote, the top two face off in a second round.

From Los Angeles Times • Jun. 6, 2026

Unless the trust is set up to pass those gains through, the trust may still owe taxes on them, even if it distributes that $300,000 in regular income every year.

From MarketWatch • May 23, 2026

Unless the Fed abandons that risk-management framework, focusing on a narrower inflation measure would not materially change policy if inflation risks are skewed one way or another.

From MarketWatch • May 22, 2026

"Nvidia represents 8% of the S&P 500. Unless there's a belief in this continued parabolic growth it's difficult for investors to get super excited, although Nvidia posted outstanding numbers," she told the BBC.

From BBC • May 21, 2026

Unless I am mistaken, it seems they no longer use the hair poultice.

From "The Interrupted Tale" by Maryrose Wood