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; on, less

Example Sentences

Then, in 2022, another amendment to the law directed courts to allow a diversion if a diagnosed mental health disorder played a significant role in the alleged crime unless there is “clear and convincing” evidence it wasn’t a motivating factor.

From Los Angeles Times

Generally it is legal to film people in public, unless they are doing something which would be considered to be private, but doing so can come under existing laws such as harassment or stalking laws.

From BBC

“Companies willing to drill out on the fringes, unless they have great economics, they’re not going to do any exploring.”

From The Wall Street Journal

“After we build this house the way we want it, we’re not moving again. Unless I’m sent up to my higher power.”

From Los Angeles Times

In separate posts, the president said he would crack down on payouts to bosses and shareholders of major US defence contractors unless the firms speed up deliveries of armaments and build new manufacturing plants.

From BBC