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

The only certainty is the Division 1 final will be played on Friday at 7 p.m. at Cal State Fullerton unless either of the finalists has a scheduling issue on that date.

From Los Angeles Times • May 26, 2026

For starters, she would have to rent an apartment, which would probably eat up most of any Social Security benefits unless she had additional support.

From MarketWatch • May 26, 2026

An arbitration panel decision would be binding on the parties for two years unless amended “by written consent of the parties.”

From The Wall Street Journal • May 25, 2026

Leclerc was so frustrated that with about 25 laps to go he asked his engineer for no more communication until the final lap unless it was for something urgent.

From BBC • May 24, 2026

“I was going to make pot pie for dinner, but unless the power comes back, it’s going to be cereal.”

From "Bye Forever, I Guess" by Jodi Meadows