# irrational number

noun, Mathematics
1.
a number that cannot be exactly expressed as a ratio of two integers.
Origin of irrational number
1545-1555
1545-55
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for irrational number
Historical Examples
• In that theory an irrational number was the ratio of two incommensurable geometric magnitudes.

• The widened idea is that even when a or x is an irrational number we may speak of a or x unit lengths by measure.

British Dictionary definitions for irrational number

## irrational number

noun
1.
any real number that cannot be expressed as the ratio of two integers, such as π
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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irrational number in Science
 irrational number   (ĭ-rāsh'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
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irrational number in Culture

### irrational number definition

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 American Heritage® New Dictionary of Cultural Literacy, Third Edition
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irrational number in Technology

mathematics
A real number which is not a rational number, i.e. it is not the ratio of two integers.
The decimal expansion of an irrational is infinite but does not end in an infinite repeating sequence of digits.
Examples of irrational numbers are pi, e and the square root of two.
(1995-04-12)

The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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### Difficulty index for irrational number

Few English speakers likely know this word

### Word Value for irrational

10
12
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