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

This is an unusual position for an exponent of the public sphere and communicative rationality to take. —Sean Williams, Harpers Magazine, 27 Jan. 2026

This is where balance and ratios come in again, bringing rationality into the world. —Thomas Patier, Artforum, 27 Jan. 2026

The world is full of bad actors—cheats, liars, tyrants, sickos—who are, ultimately, mere human beings; at least, this was how rationality would have it. —Joshua Rothman, New Yorker, 23 Jan. 2026

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

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