rule of thumb

noun

1. a general or approximate principle, procedure, or rule based on experience or practice, as opposed to a specific, scientific calculation or estimate.

2. a rough, practical method of procedure.

rule of thumb

noun

1. 1. a rough and practical approach, based on experience, rather than a scientific or precise one based on theory

   2. ( as modifier )

      a rule-of-thumb decision

rule of thumb

1. A practical principle that comes from the wisdom of experience and is usually but not always valid: “When playing baseball, a good rule of thumb is to put your best hitter fourth in the batting order.”

Word History and Origins

Origin of rule of thumb¹

First recorded in 1685–95

Idioms and Phrases

A rough and useful principle or method, based on experience rather than precisely accurate measures. For example, His work with the youth group is largely by rule of thumb. This expression alludes to making rough estimates of measurements by using one's thumb. [Second half of 1600s]

Example Sentences

“They need to have a plan, and more than a rule of thumb and arbitrary goals, to live out their retirement.”

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“The rule of thumb is, if you put your hand up in the direction that the light is coming and you see a shadow, that is enough light for the plant to sense,” she said.

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But it is a reminder that just like AI, traditional rules of thumb for investing aren’t infallible.

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“The rule of thumb is that you buy at ten and sell at twenty.”

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The general rule of thumb around AI regulation is that before you create any new law, think about what rules are already in the book.

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Related Words

• criterion