Synonyms of rationale
1
: an explanation of controlling principles of opinion, belief, practice, or phenomena
2
: an underlying reason : basis

Did you know?

If someone asserts that the word rationale refers to a ration of ale, they are wrong, but that doesn’t mean they don’t have an actual rationale (a reason, explanation, or basis) for such a claim. “Rationale looks like the words ration and ale jammed together,” they could offer, and while that is true you’d be justified in responding: “Appearances can be deceiving.” Rationale is a direct borrowing of the Latin word rationale, with which it shares the meaning “an explanation of controlling principles of opinion, belief, practice, or phenomena.” The Latin rationale comes from a form of the adjective rationalis (“rational”), which traces back to the noun ratio, meaning “reason.” While the Latin ratio is also the forebear of the English noun ration, referring to a share of something, rationale has nothing to do with a tankard (or stein, or even a pony) of beer.

Examples of rationale in a Sentence

the rationale for starting the school day an hour later is that kids will supposedly get an extra hour of sleep
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
If the once-a-decade rhythm has any rationale, in fact, the pressure for a meaningful midterm ought to be building substantially. — Ron Elving, NPR, 24 Oct. 2026 Well, the English language market is certainly growing, and that was also one of the rationales of the merger deal between All3Media and Banijay. — Nick Vivarelli, Variety, 23 Oct. 2026 Wrigley View Rooftop maintains that the Cubs haven’t explained the rationale for opposing the removal of confidentiality designations. — Michael McCann, Sportico.com, 20 Oct. 2026 Write down your entry rationale, invalidation level and position size every time, and be able to justify your decisions. — Thomas Hartmann, Forbes.com, 20 Oct. 2026 See All Example Sentences for rationale

Word History

Etymology

Latin, neuter of rationalis

First Known Use

1657, in the meaning defined at sense 1

Time Traveler
The first known use of rationale was in 1657

Browse Nearby Words

Podcast

Cite this Entry

“Rationale.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rationale. Accessed 27 Oct. 2026.

Kids Definition

rationale

noun
: a basic reason or explanation for something
Love words? Need even more definitions?

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

More from Merriam-Webster