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.
The color of your urine is a good rule of thumb for your hydration level. — Sarah Bence, Verywell Health, 22 June 2026 Our rule of thumb for feeling comfortable and confident on the go? — Julia Morlino, Travel + Leisure, 25 June 2026 As a rule of thumb, be sure to leave your pets, booze, drones and weapons at home, and don’t forget to bring lawn chairs and blankets. — John Wenzel, Denver Post, 25 June 2026 However, there’s no standing rule of thumb about what to do about interior doors. — Nafeesah Allen, Better Homes & Gardens, 22 June 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

Rhymes for rule of thumb

See All Rhymes for rule of thumb

Browse Nearby Words

rule of three
rule of thumb
rule of two and three
See all Nearby Words

Cite this Entry

“Rule of thumb.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rule%20of%20thumb. Accessed 7 Jul. 2026.

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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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