slide rule

American  

noun

1. a device for performing mathematical calculations, consisting essentially of a ruler having a sliding piece moving along it, both marked with graduated, usually logarithmic, scales: now largely replaced by the electronic calculator.

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slide rule British  

noun

1. a mechanical calculating device consisting of two strips, one sliding along a central groove in the other, each strip graduated in two or more logarithmic scales of numbers, trigonometric functions, etc. It employs the same principles as logarithm tables

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Etymology

Origin of slide rule

1655–65 for earlier sense; 1875–80 for current sense

Example Sentences

As MarketWatch has recently written, hedge-fund manager Harris “Kuppy” Kupperman, among others, has already run a slide rule over the math of the AI mania and found it comes up short.

From MarketWatch • Nov. 14, 2025

For about 350 years, humanity’s most innovative hand-held computer was something called a slide rule.

From New York Times • Feb. 8, 2024

He last sat a maths exam in 1946 when he used a slide rule, but this time he had a calculator and a magnifying glass to help with his poor eyesight.

From BBC • Aug. 25, 2022

He had a knack for math—“I used to do slide rule speed competitions,” he confesses—and majored in physics at Texas A&M University, College Station.

From Science Magazine • Jul. 27, 2022

The parting in his short gray hair was almost unnaturally straight, and his narrow toothbrush mustache looked as though he trimmed it using a slide rule.

From "Harry Potter And The Goblet Of Fire" by J. K. Rowling