# complex number

### noun

a mathematical expression (a + bi) in which a and b are real numbers and i2 = −1.

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## Nearby words

## Origin of complex number

First recorded in 1825–35

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

## British Dictionary definitions for complex number

## complex number

### noun

any number of the form a + i b, where a and b are real numbers and i = √–1See number (def. 1)

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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## Science definitions for complex number

## complex number

[ kŏm′plĕks′ ]

A number that can be expressed in terms of i (the square root of -1). Mathematically, such a number can be written a + bi, where a and b are real numbers. An example is 4 + 5i.

The American Heritage® Science Dictionary
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