Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

rationality

noun ra·tio·nal·i·ty \ ˌra-shə-ˈna-lə-tē \
|Updated on: 21 Jul 2018

Definition of rationality

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

See rationality defined for kids

Recent Examples of rationality from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rationality.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of rationality

1628

in the meaning defined at sense 1

See Words from the same year
NEW! Time Traveler

Medical Dictionary

rationality

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

medical Definition of rationality

plural rationalities
1 : the quality or state of being rational
2 : the quality or state of being agreeable to reason

Learn More about rationality

  1. See words that rhyme with rationality Nglish: Translation of rationality for Spanish speakers Britannica English: Translation of rationality for Arabic speakers Britannica.com: Encyclopedia article about rationality

Seen and Heard

What made you want to look up rationality? Please tell us where you read or heard it (including the quote, if possible).

show hide

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

gaffer

play

a lighting electrician on a movie set

Get Word of the Day daily email!

TRENDING NOW

  1. sequacious 'intellectually servile'

  2. inadmissible 'not capable of being allowed'

  3. oligarch, pejorative 'a member a government in which a small group exercises control especially for corrupt and selfish purposes'

  4. emolument 'the returns arising from office or employment usually in the form of compensation or perquisites'

  5. troll 'to harass, criticize, or antagonize especially by disparaging or mocking public statements'

SEE ALL

BROWSE DICTIONARY

rationality

Test Your Vocabulary

The Eponym Quiz

  • rubens-painting
  • Which is the best synonym of bowdlerize?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Add Diction

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

Ask the Editors

Word Games