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

The Democrats have a rare opportunity to fill the void of economic rationality left by the traditionally pro-business GOP by moving toward the political center and working with the business community. —Jeffrey Sonnenfeld, Time, 13 Jan. 2026

Newsom further revealed the limits of his rationality with his remarks on the high-speed rail boondoggle. —Sal Rodriguez, Oc Register, 9 Jan. 2026

Discipline and rationality define the Mets’ offseason so far, but a path to landing a big-name free agent always existed. —Will Sammon, New York Times, 7 Jan. 2026

This seems to me as offensive to rationality as a saint shrieking into the air. —Christian Wiman, Harpers Magazine, 30 Dec. 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