rational

adjective
ra·​tio·​nal | \ ˈrash-nəl, ˈra-shə-nᵊl\

Definition of rational 

(Entry 1 of 2)

1a : having reason or understanding
b : relating to, based on, or agreeable to reason : reasonable a rational explanation rational behavior
2 : involving only multiplication, division, addition, and subtraction and only a finite number of times
3 : relating to, consisting of, or being one or more rational numbers a rational root of an equation

rational

noun

Definition of rational (Entry 2 of 2)

: something rational specifically : rational number

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Other Words from rational

Adjective

rationally adverb
rationalness noun

Examples of rational in a Sentence

Adjective

human beings are rational creatures insisted there was a rational explanation for the strange creaking noises and that there were no such things as ghosts

Recent Examples on the Web: Adjective

Well, that’s assuming that leaders will be rational, which isn’t always the case. Eric Johnson, Recode, "Netflix will get ads, predicts the Trade Desk CEO Jeff Green," 15 Nov. 2018 Well, there’s never been any good evidence that Kim is any less rational or self-interested than leaders of Russia and China (notwithstanding the occasional hysterical headline). Robert Wright, The New Republic, "The Case for Cautious Optimism About the Trump-Kim Summit," 14 Mar. 2018 Agents can be rational or irrational, greedy or fearful, and have all sorts of restrictions and motivations. Paul J. Davies, WSJ, "A New Way to Spot the Next Financial Crisis," 18 Dec. 2018 In that fecund little valley that divides our rational and and instinctive reactions to machines, Gannon’s work thrives. James Vincent, The Verge, "Teaching robots body language offers common ground for humans and machines," 11 Nov. 2018 There are inexplicable moments: my favorite is when Amber has a rational conversation with her horse about going back to the castle (this is not a magical horse that is somehow able to answer back). Kelsea Stahler, Teen Vogue, "Netflix Original Christmas Movies: A Guide to the Cheesy Holiday Flicks," 11 Dec. 2018 Trump seems certain to walk out the peace agreement later this week, after his previous attempts to do so were stymied by more rational advisers who have since departed his administration. Chas Danner, Daily Intelligencer, "Report: Trump Aides Used Weinstein Tactics to Target Iran Deal," 6 May 2018 With that in mind, the current (lack of) action on behalf of corporate boards seems more rational. Valentina Zarya, Fortune, "Shari Redstone, Bill Cosby, The RealReal: Broadsheet April 12," 12 Apr. 2018 That’s the apparent intent: to enable unaccountable, secretive policymaking with no rational basis. Basav Sen, Fortune, "Trump Thinks Propping Up Failing Coal Is a ‘National Security’ Emergency," 31 May 2018

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

Adjective

14th century, in the meaning defined at sense 1a

Noun

1601, in the meaning defined above

History and Etymology for rational

Adjective

Middle English racional, from Anglo-French racionel, from Latin rationalis, from ration-, ratio

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Statistics for rational

Last Updated

16 Jan 2019

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Time Traveler for rational

The first known use of rational was in the 14th century

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More Definitions for rational

rational

adjective

English Language Learners Definition of rational

: based on facts or reason and not on emotions or feelings

: having the ability to reason or think about things clearly

rational

adjective
ra·​tio·​nal | \ ˈra-shə-nᵊl \

Kids Definition of rational

1 : having the ability to reason Humans are rational creatures.
2 : based on or showing reason rational thinking a rational decision

Other Words from rational

rationally adverb

rational

adjective
ra·​tio·​nal | \ ˈrash-nəl, -ən-ᵊl \

Medical Definition of rational 

1a : having reason or understanding
b : relating to, based on, or agreeable to reason a rational explanation rational behavior
2 : using medical treatments based on reason or general principles used especially of an ancient school of physicians — compare empirical sense 1a

Other Words from rational

rationally \ -​ē \ adverb

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rational

adjective
ra·​tio·​nal | \ ˈra-shə-nəl \

Legal Definition of rational 

1 : having reason or understanding
2 : relating to, based on, or guided by reason, principle, fairness, logic, a legitimate state interest, or a consideration of fact age distinctions are not subject to strict scrutiny, but they must have a rational relationship to a legitimate state interestIn re J. M., 642 A.2d 1062 (1994)

Other Words from rational

rationality \ ˌra-​shə-​ˈna-​lə-​tē \ noun
rationally adverb

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More from Merriam-Webster on rational

Rhyming Dictionary: Words that rhyme with rational

Thesaurus: All synonyms and antonyms for rational

Spanish Central: Translation of rational

Nglish: Translation of rational for Spanish Speakers

Britannica English: Translation of rational for Arabic Speakers

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