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 the settlement fund is established and distributes payments, that scenario is unlikely.

From Los Angeles Times • Jul. 1, 2026

Unless they get on board, the U.S. nuclear renaissance will remain an aspiration.

From Barron's • Jun. 26, 2026

"Unless we drastically cut down the emission of greenhouse gases, global warming is not going to stop. In fact, it will accelerate," Deoras said.

From BBC • Jun. 24, 2026

Unless this property is based in France, Germany, Ireland or the U.K.,

From MarketWatch • Jun. 24, 2026

Unless they were using him as target practice, they didn’t want to be associated with their foster brother, and that was all right with Danny.

From "The Way to Rio Luna" by Zoraida Cordova