complex number
nounUK /ˈkɒm.plɛks ˈnʌm.bə/
US /ˈkɑːm.plɛks ˈnʌm.bɚ/
A complex number is a number made of two parts, a real part and an imaginary part, like 3 + 2i.
In math class, we learned that 4 + 3i is a complex number.
OTHER MEANINGS
2. A number that can be written as a + bi, where a and b are real numbers and i is the square root of -1.
Every real number is also a complex number with an imaginary part of zero.
3. A point on the complex plane, plotted with a real axis and an imaginary axis.
The complex number 2 + 3i sits at the point (2, 3) on the complex plane.
4. A value used in engineering and physics to describe waves and signals.
Electrical engineers use complex numbers to describe how current flows in a circuit.