irrational number

American  

noun

Mathematics.

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

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irrational number British  

noun

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

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irrational number Scientific  

/ ĭ-răsh′ə-nəl /

1. 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.

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irrational number Cultural  

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

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The square roots of most whole numbers are irrational numbers.

Etymology

Origin of irrational number

First recorded in 1545–55