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
rationally
adverb
rationalness
noun
: something rational
specifically
: rational number
Synonyms
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
Gabriela Sandoval, The Mercury News, 13 Apr. 2024
One man scrambled our common sense, seduced our better natures and rational selves.
—Wesley Morris, New York Times, 12 Apr. 2024
These are mystifying events with rational explanations.
—Brian Klaas, The Atlantic, 10 Apr. 2024
Moral compass Moral fibre One is rational, explicit, and defined by one’s social or professional community; the other is emotional, deep-seated, and dictated by one’s conscience or god.
—Hazlitt, 10 Apr. 2024
At times our laughter accidentally propels us onto the comedian’s side, despite certain rational objections.
—Miriam Katz, Los Angeles Times, 5 Apr. 2024
Kipling Wes Crossbody While a tote or backpack might seem like the most rational choice for carrying an abundance of personal items, some crossbody bags can hold just as much (except maybe a laptop or tablet).
—Ali Faccenda, Travel + Leisure, 31 Mar. 2024
The company behind the money-losing Truth Social platform has zoomed well beyond what critics say is rational, as fans of former president Donald Trump keep pushing it higher.
—Elaine Kurtenbach, Quartz, 28 Mar. 2024
Fighting against all odds can be rational for actors if the consequences of ending the conflict seem worse than continuing it.
—Branislav L. Slantchev, Foreign Affairs, 1 Apr. 2024
Lyndie Chiou, Quanta Magazine, 5 Mar. 2024
Is there a set of points on that line, on the number line, which is larger than the natural numbers, larger than the rationals, but smaller than the whole line itself?
—Steven Strogatz, Quanta Magazine, 19 Apr. 2023
Empirical inquiry—often considered strictly a province of the rational—can also be fueled by fervent belief.
—Faith Hill, The Atlantic, 6 May 2022
But other states and cities are taking their positive revenues as a rational for deep tax cuts.
—Richard McGahey, Forbes, 14 Apr. 2022
The gas supply in 1974 was reported to have bottomed out at only about 20% below normal, but drivers acted about 50% below rational.
—Los Angeles Times, 22 Mar. 2022
In the book, Starhawk defines magic as awakening deeper levels of consciousness beyond the rational.
—WSJ, 8 Dec. 2021
Darkside is something entirely distinct, a surreal form of magic at war with the rational.
—Washington Post, 23 July 2021
In her 2017 essay, Khan also pointed to platforms’ creating incentives for companies to favor growth over profits, which ostensibly makes predatory pricing rational.
—Jessica Melugin, National Review, 22 June 2021
Adjective
While some perceived my ordeal as an outcome of the principles of supply and demand, with property owners making rational choices to maximize profits, the broader housing crisis illustrates the consequences of wealth concentrated in the hands of a few.
—Gabriela Sandoval, The Mercury News, 13 Apr. 2024
One man scrambled our common sense, seduced our better natures and rational selves.
—Wesley Morris, New York Times, 12 Apr. 2024
These are mystifying events with rational explanations.
—Brian Klaas, The Atlantic, 10 Apr. 2024
Moral compass Moral fibre One is rational, explicit, and defined by one’s social or professional community; the other is emotional, deep-seated, and dictated by one’s conscience or god.
—Hazlitt, 10 Apr. 2024
At times our laughter accidentally propels us onto the comedian’s side, despite certain rational objections.
—Miriam Katz, Los Angeles Times, 5 Apr. 2024
Kipling Wes Crossbody While a tote or backpack might seem like the most rational choice for carrying an abundance of personal items, some crossbody bags can hold just as much (except maybe a laptop or tablet).
—Ali Faccenda, Travel + Leisure, 31 Mar. 2024
The company behind the money-losing Truth Social platform has zoomed well beyond what critics say is rational, as fans of former president Donald Trump keep pushing it higher.
—Elaine Kurtenbach, Quartz, 28 Mar. 2024
Fighting against all odds can be rational for actors if the consequences of ending the conflict seem worse than continuing it.
—Branislav L. Slantchev, Foreign Affairs, 1 Apr. 2024
Noun
At the time the database had a little over 3 million elliptic curves over the rationals.
—Lyndie Chiou, Quanta Magazine, 5 Mar. 2024
Is there a set of points on that line, on the number line, which is larger than the natural numbers, larger than the rationals, but smaller than the whole line itself?
—Steven Strogatz, Quanta Magazine, 19 Apr. 2023
Empirical inquiry—often considered strictly a province of the rational—can also be fueled by fervent belief.
—Faith Hill, The Atlantic, 6 May 2022
But other states and cities are taking their positive revenues as a rational for deep tax cuts.
—Richard McGahey, Forbes, 14 Apr. 2022
The gas supply in 1974 was reported to have bottomed out at only about 20% below normal, but drivers acted about 50% below rational.
—Los Angeles Times, 22 Mar. 2022
In the book, Starhawk defines magic as awakening deeper levels of consciousness beyond the rational.
—WSJ, 8 Dec. 2021
Darkside is something entirely distinct, a surreal form of magic at war with the rational.
—Washington Post, 23 July 2021
In her 2017 essay, Khan also pointed to platforms’ creating incentives for companies to favor growth over profits, which ostensibly makes predatory pricing rational.
—Jessica Melugin, National Review, 22 June 2021
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'rational.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
Etymology
Adjective
Middle English racional, from Anglo-French racionel, from Latin rationalis, from ration-, ratio
First Known Use
Adjective
14th century, in the meaning defined at sense 1a
Noun
1601, in the meaning defined above
Time Traveler
The first known use of rational was
in the 14th century
Phrases Containing rational
Dictionary Entries Near rational
Cite this Entry
“Rational.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rational. Accessed 19 Apr. 2024.
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Kids Definition
rational
1 of 2 adjective
ra·tio·nal
ˈrash-nəl 
-ən-ᵊl
1
a
: having the ability to reason
rational beings
b
: relating to, based on, or showing reason : reasonable sense 2
rational behavior
2
: relating to or involving rational numbers
a rational fraction
rationally
adverb
-ē
rational
2 of 2 noun
: something rational
especially
: rational number
Medical Definition
rational
adjective
ra·tio·nal
ˈrash-nəl, -ən-ᵊl
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 sense 1a
Legal Definition
rational
adjective
ra·tio·nal
ˈra-shə-nəl
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)
In re J. M., 642 A.2d 1062 (1994)
rationally
adverb
More from Merriam-Webster on rational
Nglish: Translation of rational for Spanish Speakers
Britannica English: Translation of rational for Arabic Speakers
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