# complex number

Save This Word!

### noun

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

## QUIZZES

#### QUIZ YOURSELF ON “THEIR,” “THERE,” AND “THEY’RE”

Are you aware how often people swap around “their,” “there,” and “they’re”? Prove you have more than a fair grasp over these commonly confused words.

Question 1 of 7

Which one of these commonly confused words can act as an adverb or a pronoun?

## Origin of complex number

First recorded in 1825–35

## Words nearby complex number

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

## Example sentences from the Web for complex number

## 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
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Scientific 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
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.