| complex number | A number in the form a + bi, where a and b are real numbers and i is the square root of −1. |
| imaginary number | A number in the form bi, where b is a real number and i is the square root of −1. |
| imaginary part | The imaginary term, bi, in a complex number a + bi. |
| real part | The real term, a, in a complex number a + bi. |