# irrational number

### noun Mathematics.

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

## RELATED CONTENT

## Nearby words

- irradiant,
- irradiate,
- irradiation,
- irradicable,
- irrational,
- irrationalism,
- irrationality,
- irrationalize,
- irrawaddy,
- irreal

## Origin of irrational number

First recorded in 1545–55

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

## irrational number

### noun

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

## irrational number

[ĭ-răsh′ə-nəl]

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

## irrational number

A number that cannot be expressed as the ratio of two whole numbers.

## Note

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.