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

See Examples For:

unless

The cuts will be automatic unless Congress acts to strengthen the system.

From MarketWatch ● Oct. 12, 2026

“Certain lyrics made people talk like we had written them about 9/11, but there’s no way they could have been about 9/11 unless we were prophets of some kind,” Malakian said.

From Los Angeles Times ● Oct. 12, 2026

Better-tailored air alerts can limit the number of businesses that have to shut down and avoid sending civilians to shelters unless a threat is imminent.

From The Wall Street Journal ● Oct. 11, 2026

"At the same time, the warning could be interpreted as stopping short of completely foreclosing inter-Korean dialogue: essentially telling Seoul not to interfere unless it has something substantial to offer."

From Barron's ● Oct. 8, 2026

True, her salary was generous, but Lady Constance rarely thought to pay it unless asked.

From "The Interrupted Tale" by Maryrose Wood