squarerootofminusone
nounUK /ˌskwɛə ruːt əv ˈmaɪnəs wʌn/
US /ˌskwɛr ruːt əv ˈmaɪnəs wʌn/
A special number that, when multiplied by itself, gives minus one.
In math class, we learned that the square root of minus one is written as i.
OTHER MEANINGS
2. The imaginary unit used in complex numbers, denoted by the letter i.
Engineers use the square root of minus one to describe alternating currents.
3. A concept in algebra that extends the real number system to complex numbers.
The square root of minus one is the building block of complex arithmetic.
4. A playful or informal way to refer to an impossible or imaginary quantity.
Asking for a real answer to that is like asking for the square root of minus one.