rule of thumb

noun phrase

1
: a method of procedure based on experience and common sense
2
: a general principle regarded as roughly correct but not intended to be scientifically accurate

Examples of rule of thumb in a Sentence

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.
Three good rules of thumb: Pair with something unexpected. Erika Veurink, Vogue, 29 July 2025 The actual rule of thumb is that the new lineup (almost) always releases on the first Tuesday of the month and the games are revealed the previous Wednesday. Erik Kain, Forbes.com, 27 July 2025 Key takeaways: The pursuit of ever-smaller tracking tags To not burden an animal, the rule of thumb is that tracking tags should be no heavier than 2 percent of an animal's mass. Moira Donovan, Smithsonian Magazine, 21 July 2025 Your talks don’t have to be exactly one-minute long, but sticking to three to eight minutes is a good rule of thumb, Davis says. Renée Onque, CNBC, 26 June 2025 See All Example Sentences for rule of thumb

Word History

First Known Use

circa 1658, in the meaning defined at sense 1

Time Traveler
The first known use of rule of thumb was circa 1658

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Cite this Entry

“Rule of thumb.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rule%20of%20thumb. Accessed 3 Aug. 2025.

Kids Definition

rule of thumb

1
: a method based on experience and common sense
2
: a general principle that is roughly correct
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