rational

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

|Updated on: 19 Jun 2018

Examples: rational in a Sentence

Definition of rational

1 a : 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

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rationally

adverb

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rationalness

noun

See rational defined for English-language learners

See rational defined for kids

Examples of rational in a Sentence

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 of rational from the Web

Nervous Nelly The tough part about such dread is that some of it is rational.

— carolyn hax, Cincinnati.com, "Carolyn Hax: Life's perfect, except for the crippling anxiety," 10 May 2018
The circumstances should vindicate Weber to any rational fan.

— vahe gregorian, kansascity, "K-State's Bruce Weber now must meet expectations instead of defying them," 1 June 2018
Among women privileged enough—economically, biologically, logistically—to have a choice in their method of feeding a baby, the pressure to breastfeed can sometimes eclipse rational consideration.

— laura goode, Glamour, "I Hated Breastfeeding—So I Quit," 22 May 2018
There are plenty of rational reasons to oppose the existence of the monarchy in the 21st century.

— sophie gilbert, The Atlantic, "Thoroughly Modern Meghan," 21 May 2018
As is the case for most of us, the extended members of Meghan’s clan include some relatively rational and steady people, and some who are a bit more volatile, self-promoting, or simply ignorant of the ways of tabloid media.

— jill filipovic, Teen Vogue, "Meghan Markle’s Royal Wedding Is Not Your Average Disney Princess Fantasy," 19 May 2018
That should sound seriously insane to rational people — this idea that you are being personally targeted by the government, on some secret list kept inside a drawer at a BLM field office.

— leah sottile, Longreads, "Bundyville Chapter Four: The Gospel of Bundy," 18 May 2018
Sundby thinks that’s because people gave up trying to argue that the courts are wholly rational.

— jill lepore, The New Yorker, "The Rise of the Victims’-Rights Movement," 14 May 2018
But as long as ecologists have warned about the danger of invasive species, others have asked whether this kind of language—which carries connotations of war and xenophobia—could cloud the science and make rational discussion more difficult.

— amy crawford, Smithsonian, "Why We Should Rethink How We Talk About “Alien” Species," 9 Jan. 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.

Origin and Etymology of rational

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

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First Known Use: 14th century

in the meaning defined at sense 1a

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rational Synonyms

rational

noun

Definition of rational

: something rational; specifically : rational number

First Known Use of rational

1601

in the meaning defined above

See Words from the same year

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RATIONAL Defined for English Language Learners

rational

adjective

Definition of rational for English Language Learners

: based on facts or reason and not on emotions or feelings
: having the ability to reason or think about things clearly

RATIONAL Defined for Kids

rational

adjective ra·tio·nal \ ˈra-shə-nᵊl \

Definition of rational for Students

1 : having the ability to reason

Humans are rational creatures.

2 : based on or showing reason

rational thinking

a rational decision

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rationally

adverb

Medical Dictionary

rational

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

medical Definition of rational

1 a : 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 1a

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rationally

play \-ē\ adverb

Law Dictionary

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 interest
—In re J. M., 642 A.2d 1062 (1994)

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