un·​less | \ən-ˈles, ˈən-ˌles\

Definition of unless 

(Entry 1 of 2)

1 : except on the condition that : under any other circumstance than

2 : without the accompanying circumstance or condition that : but that : but



Definition of unless (Entry 2 of 2)

: except possibly : except

Examples of unless in a Sentence

Recent Examples on the Web: Preposition

In these cases, the FDA says, the infection can also spread to the bloodstream and may become life-threatening unless the person gets prompt treatment with antibiotics. Sarah Jacoby, SELF, "4 Types of Duncan Hines Cake Mix Recalled Amid Salmonella Outbreak," 6 Nov. 2018 Last December Mrs May agreed that Northern Ireland would retain regulatory and customs alignment with the EU unless another way could be found to forestall a hard border with Ireland. The Economist, "The EU digests Britain’s new Brexit plan," 11 July 2018 Louisville already has three scholarships open now, and unless Mack and his staff find a late addition for this coming season, those will carry over to the 2019 group. Jeff Greer, The Courier-Journal, "U of L Insider: Why the next few weeks are vital for Chris Mack, Cards," 9 July 2018 Staszkiewicz plans to do the same at Minnesota unless the Gophers find a walk-on spot for a player who scored more than 100 goals as a prep. Mark Stewart, Milwaukee Journal Sentinel, "Seniors lead a charge that nets the Lancers a second straight WIAA title," 16 June 2018 But in Florida, felons often lose those rights for the rest of their lives unless the governor and Cabinet vote to restore them. Scott Maxwell, OrlandoSentinel.com, "In Florida, getting back civil rights means groveling to politicians," 11 July 2018 For minors, medical privacy rules may prevent sampling unless each child is designated a legal guardian or representative, which is obviously problematic in this case. John Moore, National Geographic, "Could DNA Testing Reunite Immigrant Families? Get the Facts.," 25 June 2018 Cleveland doesn’t have the assets to swing a trade for a player of Leonard’s caliber, unless, of course, LeBron James is included in the deal. Steven Ruiz, For The Win, "Betting odds on where Kawhi Leonard will play next season," 15 June 2018 Webworms don't do enough damage to be significant, unless a plant is small. Ellen Nibali, baltimoresun.com, "Garden Q&A: Be wary of the 'bathtub effect'," 12 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unless.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of unless


15th century, in the meaning defined at sense 1


circa 1532, in the meaning defined above

History and Etymology for unless


Middle English unlesse, alteration of onlesse, from on + lesse less

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The first known use of unless was in the 15th century

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English Language Learners Definition of unless

—used to say what will happen, be done, or be true if something else does not happen, is not done, or is not true


un·​less | \ən-ˈles \

Kids Definition of unless

: except on the condition that You can't have dessert unless you finish your dinner.

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Comments on unless

What made you want to look up unless? Please tell us where you read or heard it (including the quote, if possible).


something that serves to warn or remind

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