What is imaginary numbers?
a numbers which, after multiplying, give a negative result
a numbers that, when squared, has a negative result
all numbers which are not rational numbers
Essentially, an imaginary number is the square root of a negative number and does not have a tangible value. While it is not a real number — that is, it cannot be quantified on the number line - imaginary numbers are "real" in the sense that they exist and are used in math. Imaginary numbers are particularly applicable in electronics.