imaginary
//ɪˈmædʒ.ɪ.nər.i//
Adjective
imaginaryCanonical form
1
Existing only in the mind or imagination; not real or tangible.
As a child, she had an imaginary friend who went everywhere with her.
2
(Mathematics) Relating to or denoting a number that is expressed in terms of the square root of a negative number, especially the square root of -1.
The imaginary unit i is defined as the square root of -1.