unless

[ uhn-les, uhn- ]
See synonyms for unless on Thesaurus.com
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.

Origin of unless

1
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

Words Nearby unless

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use unless in a sentence

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

    How to Know the Ferns | S. Leonard Bastin
  • This was why we resolved, at the time of our arrival, not to baptize any adults unless they were previously well catechized.

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

    Assimilative Memory | Marcus Dwight Larrowe (AKA Prof. A. Loisette)
  • If we set him adrift the poor child would starve—unless the cat got him.

    The Tale of Grandfather Mole | Arthur Scott Bailey
  • The intensity of his sensations seemed inexplicable, unless some reality, some truth, lay behind them.

    The Wave | Algernon Blackwood

British Dictionary definitions for unless

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

Origin of unless

1
C14: onlesse, from on on + lesse less; compare French à moins que, literally: at less than

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012