rationality

noun

ra·​tio·​nal·​i·​ty ˌra-shə-ˈna-lə-tē 

plural rationalities

1

: the quality or state of being rational

2

: the quality or state of being agreeable to reason : reasonableness

3

: a rational opinion, belief, or practice

—usually used in plural

Examples of rationality in a Sentence

Recent Examples on the Web

And, at his best, there is an icy rationality, even on the biggest stages, in the biggest moments. —Jack Pitt-Brooke, New York Times, 3 Dec. 2025

Debates about Cold War rationality reprised an earlier discourse about criminal nature versus nurture and the educability of felons. —Big Think, 27 Nov. 2025

This seems to me as offensive to rationality as a saint shrieking into the air. —Christian Wiman, Harpers Magazine, 23 Nov. 2025

There is also no need to worry about the rationality of these states. —Moritz S. Graefrath, Foreign Affairs, 19 Nov. 2025

Word History

First Known Use

1628, in the meaning defined at sense 1

Phrases Containing rationality

• hyper-rationality

Rhymes for rationality

• abnormality
• cardinality
• commonality
• communality
• cordiality
• corporeality
• criminality
• criticality
• functionality
• generality
• geniality
• hospitality

Kids Definition

rationality

noun

ra·​tio·​nal·​i·​ty ˌrash-ə-ˈnal-ət-ē 

: the quality or state of being rational

Medical Definition

rationality

noun

ra·​tio·​nal·​i·​ty ˌrash-ə-ˈnal-ət-ē 

plural rationalities

1

: the quality or state of being rational

2

: the quality or state of being agreeable to reason