square root

American  

noun

1. a quantity of which a given quantity is the square.

   The quantities +6 and −6 are square roots of 36 since (+6)×(+6)=36 and (−6)×(−6)=36.

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square root British  

noun

1. a number or quantity that when multiplied by itself gives a given number or quantity

   2 is a square root of 4, usually written √4 or 41/2

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square root Scientific  

1. A number that, when squared, yields a given number. For example, since 5 × 5 = 25, the square root of 25 (written √25) is 5.

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square root Cultural  

1. A number that, when multiplied by itself, will result in a given number. The square root of four is two; the square root of one hundred is ten.

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Discover More

The square roots of many numbers, such as three, are irrational numbers.

Etymology

Origin of square root

First recorded in 1550–60

Example Sentences

Why is the square root of -1 called i?

From Salon • Jul. 29, 2024

“It’s the square root of pi, so take the square root of 3.1416,” Kelly cracked of his team’s chances in that scenario.

From Los Angeles Times • Oct. 29, 2023

The whole process takes time proportional to the square root of the number of boxes: Increasing that number by a factor of 100 only increases the runtime by a factor of 10.

From Scientific American • Sep. 27, 2023

England gave them the square root of nothing.

From BBC • Sep. 9, 2023

Everyone in the Pythagorean brotherhood was already tight-lipped—nobody was allowed even to take written notes—and the incommensurability of the square root of two became the deepest, darkest secret of the Pythagorean order.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife