unless

[ uhn-les, uhn- ]

conjunction

1. except under the circumstances that:

   I'll be there at nine, unless the train is late.

preposition

1. except; but; save:

   Nothing will come of it, unless disaster.

unless

/ ʌnˈlɛs /

conjunction

1. subordinating except under the circumstances that; except on the condition that

   they'll sell it unless he hears otherwise

preposition

1. rare.
   except

Word History and Origins

Origin of unless¹

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

Word History and Origins

Origin of unless¹

C14: onlesse , from on on + lesse less ; compare French à moins que, literally: at less than

Example Sentences

Unless there is a court decision that changes our law, we are OK.

From The Daily Beast

It is grandstanding for a right rarely protected unless under immediate attack.

From The Daily Beast

They had rarely seen their own fathers carry small children unless their mothers were ill.

From The Daily Beast

Which is impossible unless people talk publicly rather than letting each crime be its own isolated incident.

From The Daily Beast

In some ways I never got out of that unless realizing… well, that kind of seals it off.

From The Daily Beast

For instance, the Limestone Polypody is not happy unless there is a certain amount of lime present in the soil.

From Project Gutenberg

This was why we resolved, at the time of our arrival, not to baptize any adults unless they were previously well catechized.

From Project Gutenberg

However great the power of Revival, there is no memory unless there was a First Impression.

From Project Gutenberg

If we set him adrift the poor child would starve—unless the cat got him.

From Project Gutenberg

The intensity of his sensations seemed inexplicable, unless some reality, some truth, lay behind them.

From Project Gutenberg