rationality
Americannoun
plural
rationalities-
the state or quality of being rational.
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the possession of reason.
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agreeableness to reason; reasonableness.
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the exercise of reason.
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a reasonable view, practice, etc.
noun
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the state or quality of being rational or logical
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the possession or utilization of reason or logic
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a reasonable or logical opinion
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economics the assumption that an individual will compare all possible combinations of goods and their prices when making purchases
Other Word Forms
Etymology
Origin of rationality
First recorded in 1560–70, rationality is from the Late Latin word ratiōnālitās reasonableness. See rational, -ity
Explanation
Use the noun rationality to refer to the state of being sensible or having good judgment. People may question your rationality if you insist on jumping into freezing water in January and skydiving for the rest of the year. The noun rationality also means the state of being agreeable to reason or being based on logic. If you have to pick a pre-school for your child, you should base your decision on rationality and not an illogical reaction, such as how many of the kids eventually go to Ivy League universities. The newer school may look better on the surface, but the older building may have better teachers, a more interesting curriculum, and be closer to your home.
Vocabulary lists containing rationality
John Nash (1928-2015) Tribute List
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"Simon's Saga," Vocabulary from Episode 21
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167 Vocabulary words from the Supreme Court's DOMA Decision
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
According to Maria Almudena Claassen, a postdoctoral fellow at the Center for Adaptive Rationality at the Max Planck Institute for Human Development, this idea creates a misleading impression.
From Science Daily • Jan. 5, 2026
Stella's criticism of the FIA was shared by Mercedes team principal Toto Wolff, who said of the governing body: "Rationality needs to win and for me it doesn't look like this at the moment."
From BBC • Dec. 2, 2024
Rationality and purely material concerns are often secondary.
From Salon • May 17, 2024
But it’s apparently been downhill for him intellectually ever since, if this excerpt from a New York Times review of his new book Rationality is any indication:
From Slate • Sep. 29, 2021
This feeling of the sufficiency of the present moment, of its absoluteness,—this absence of all need to explain it, account for it, or justify it,—is what I call the Sentiment of Rationality.
From The Will to Believe : and Other Essays in Popular Philosophy by James, William
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
