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.
As a rule of thumb, Ruben Niebla maps out the rotation as far as three weeks out. Jeff Sanders, San Diego Union-Tribune, 1 May 2026 To err on the cautious side, two hours is a good rule of thumb. Jessica Safavimehr, Southern Living, 30 Apr. 2026 Even aiming to divide them every 3 to 5 years isn't a good rule of thumb because some bulbs multiply faster than others. Andy Wilcox, Better Homes & Gardens, 29 Apr. 2026 Saltman says a good rule of thumb is to just keep two to three linen sets per bed and two to three sets of towels per person. Tessa Cooper, The Spruce, 16 Apr. 2026 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 6 May. 2026.

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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