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# irrational number

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noun Mathematics.

a number that cannot be exactly expressed as a ratio of two integers.

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## Origin of irrational number

First recorded in 1545–55

## Words nearby irrational number

irradicable, irrational, irrationalism, irrationality, irrationalize, irrational number, Irrawaddy, irreal, irrebuttable, irreclaimable, irreconcilable

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

## How to use irrational number in a sentence

## British Dictionary definitions for irrational number

irrational number

noun

any real number that cannot be expressed as the ratio of two integers, such as π

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Scientific definitions for irrational number

irrational number

[ ĭ-răsh′ə-nəl ]

A number that cannot be expressed as a ratio between two integers and is not an imaginary number. If written in decimal notation, an irrational number would have an infinite number of digits to the right of the decimal point, without repetition. Pi and the square root of 2 (√2) are irrational numbers.

The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

## Cultural definitions for irrational number

## notes for irrational number

The square roots of most whole numbers are irrational numbers.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.