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.
One rationale was that Michigan quarterback Dennis Franklin broke his collarbone late in the Ohio State game, but Schembechler didn’t buy it. — The Athletic College Football Staff, New York Times, 16 Sep. 2026 While the Fed’s action was expected, the rationale behind the hike was unusual. — Jeff Cox, CNBC, 16 Sep. 2026 While there are plenty of rationales, CBS News will have to be patient and hope that viewers will sample the program, which largely had the same look as last year despite Weiss’ changes. — Los Angeles Times, 15 Sep. 2026 Treat rationale as evidence of what people believed, not necessarily why something happened. — Srini Attili, Forbes.com, 15 Sep. 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

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Cite this Entry

“Rationale.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rationale. Accessed 26 Sep. 2026.

Kids Definition

rationale

noun
: a basic reason or explanation for something
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