ra·​tio·​nale | \ ˌra-shə-ˈnal How to pronounce rationale (audio) \

Definition of rationale

1 : an explanation of controlling principles of opinion, belief, practice, or phenomena
2 : an underlying reason : basis

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Did You Know?

The word rationale appeared in the second half of the 17th century, just in time for the Age of Reason. It is based on the Latin ratio, which means "reason," and rationalis, which means "endowed with reason." At first, rationale meant "an explanation of controlling principles" ("a rationale of religious practices," for example), but soon it began to refer to the underlying reason for something (as in "the rationale for her behavior"). The latter meaning is now the most common use of the term. The English word ratio can also mean "underlying reason" (in fact, it had this meaning before rationale did), but in current use, that word more often refers to the relationship (in number, quantity, or degree) between things.

Examples of rationale in a Sentence

the rationale for starting the school day an hour later is that kids will supposedly get an extra hour of sleep

Recent Examples on the Web

This strikes me as a rationale for studying the humanities. Paula Marantz Cohen, WSJ, "Arthur Miller’s ‘Everyman’ Is an Antidote to Identity Politics," 22 Feb. 2019 And by that rationale, Beck could also be back in one form or another. Amy Mackelden, Harper's BAZAAR, "Everything You Need to Know About You Season 2," 13 Jan. 2019 Which means the Trump administration would have to offer some other public rationale. Evan Horowitz, BostonGlobe.com, "Families will be kept together — in detention. What does Trump hope to gain?," 20 June 2018 The other rationale is that menu labeling will inspire competition among restaurants to produce options that are more healthful. Caitlin Dewey, chicagotribune.com, "How many calories are in that pizza? Chain restaurants now have to tell you.," 7 May 2018 This was their rationale for getting around the obvious and important inhibitions against such meddling. Holman W. Jenkins, WSJ, "Mueller’s Report Will Be a Bore," 1 Jan. 2019 In addition to moving the goalposts about Russia, Giuliani also tried to walk back his previous rationale about why Trump made hush payments to women in the months leading up to the 2016 election. Aaron Rupar, Vox, "Trump’s lawyer isn’t exactly denying that Trump had foreknowledge of WikiLeaks dumps," 17 Dec. 2018 The rationale for this is simple: Studies show medical marijuana can effectively treat chronic pain, which opioids are commonly used for. German Lopez, Vox, "Marijuana is legal for medical purposes in 32 states," 14 Nov. 2018 This can provide a seeming rationale for those crazy beliefs. Galadriel Watson, Discover Magazine, "Why We Feel the Need to Knock On Wood," 17 Oct. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rationale.' 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 rationale

1657, in the meaning defined at sense 1

History and Etymology for rationale

Latin, neuter of rationalis

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Last Updated

1 Mar 2019

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The first known use of rationale was in 1657

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English Language Learners Definition of rationale

somewhat formal : the reason or explanation for something


ra·​tio·​nale | \ ˌra-shə-ˈnal How to pronounce rationale (audio) \

Kids Definition of rationale

: a basic explanation or reason for something What is the rationale behind your decision?

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Comments on rationale

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


the range of authority or knowledge

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