ra·tio·nale | \ˌra-shə-ˈnal \

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

Now the far right is using Comey’s decision to break FBI protocol in order to placate Republicans as a rationale to demand breaking FBI protocol to help Republicans again, this time by quashing an investigation of Trump. Jonathan Chait, Daily Intelligencer, "Trump’s Latest and Most Insane New Theory for Shutting Down Mueller Probe," 25 June 2018 Critics have said Trump not only risks a trade war but other countries using national security grounds as a rationale for placing tariffs on American exports, including agricultural goods and autos. Todd Spangler, Detroit Free Press, "Canadian Prime Minister Justin Trudeau slams Trump on tariffs," 31 May 2018 And by invoking national security concerns as the rationale for the action, the president was setting a precedent that could give other countries more wiggle room to use security as a reason for imposing tariffs on American goods. New York Times, "The Trump Steel Tariffs Are Economically Small and Symbolically Huge," 2 Mar. 2018 Previously, the White House had cited only the false statements to Pence as a rationale for dismissing Flynn. Carol D. Leonnig, Sari Horwitz And Josh Dawsey, Houston Chronicle, "Mueller seeks to question Trump about Flynn and Comey departures," 23 Jan. 2018 But Trump’s rationale for the addition $100 billion seems to be pure oneupmanship. Zeeshan Aleem, Vox, "The looming US-China trade war, explained," 3 May 2018 Interrupting mirror face is uncomfortable for interrupter and interrupted alike, but there’s no need to defend mirror face with words like empowerment or self-esteem, today’s preferred rationale for female appearances. Molly Fischer, The Cut, "Mirror Face," 2 Apr. 2018 Bankruptcies are often used to cleave profitable assets from legacy liability, with the economic rationale of giving a promising business a new start. Tiffany Kary, Bloomberg.com, "Weinstein Co. Files for Chapter 11 Bankruptcy," 20 Mar. 2018 Bankruptcies are often used to cleave profitable assets from legacy liability, with the economic rationale of giving a promising business a new start. Anchorage Daily News, "Weinstein Co. files bankruptcy with plan to sell film assets," 20 Mar. 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

11 Oct 2018

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Time Traveler for rationale

The first known use of rationale was in 1657

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English Language Learners Definition of rationale

: the reason or explanation for something


ra·tio·nale | \ˌra-shə-ˈnal \

Kids Definition of rationale

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

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a generally accepted meaning of a word

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