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counterfactual

[koun-ter-fak-choo-uh l]
noun Logic.
  1. a conditional statement the first clause of which expresses something contrary to fact, as “If I had known.”

Origin of counterfactual

First recorded in 1945–50; counter- + factual
Related formscoun·ter·fact, nouncoun·ter·fac·tu·al·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for counter-fact

counterfactual

adjective
  1. expressing what has not happened but could, would, or might under differing conditions
noun
  1. a conditional statement in which the first clause is a past tense subjunctive statement expressing something contrary to fact, as inif she had hurried she would have caught the bus
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
Word Origin and History for counter-fact

counterfactual

adj.

1946, from counter- + factual.

Online Etymology Dictionary, © 2010 Douglas Harper