complex number, complex quantity, imaginary number, imaginary (adj)

(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1

fanciful, imaginary, notional (adj)

not based on fact; unreal

"the falsehood about some fanciful secret treaties"- F.D.Roosevelt; "a small child's imaginary friends"; "to create a notional world for oneself"

imaginary (Noun)

Imagination; fancy.

imaginary (Noun)

An imaginary quantity.

imaginary (Adjective)

existing only in the imagination

imaginary (Adjective)

of a number, having no real part; that part of a complex number which is a multiple of the square root of -1.