rational

1 of 2

adjective

ra·​tio·​nal ˈrash-nəl 

ˈra-shə-nᵊl

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

rational

2 of 2

noun

: something rational

specifically : rational number

Synonyms

Adjective

• intelligent
• reasonable
• reasoning
• thinking

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

Adjective

Strengths: Analytical, self-sufficient, trustworthy, calm, rational, objective, perceptive. —Stephanie Sengwe, Peoplemag, 25 Apr. 2024

Drake said he’s faced many tough times in the business when the rational thing to do would have been to shut it down. —Jireh Deng, Los Angeles Times, 24 Apr. 2024

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

Phrases Containing rational

• anti-rational
• hyper-rational
• rational function
• rational number
• sub-rational

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

-ē

adverb

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

rationally

-ē 

adverb

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)

rationality

ˌra-shə-ˈna-lə-tē 

noun

rationally adverb