Imaginary /(?)/

Im·ag·i·na·ry

Imaginary

a.
  1. Existing only in imagination or fancy; not real; fancied; visionary; ideal.
    Wilt thou add to all the griefs I suffer Imaginary ills and fancied tortures?

Phrases & Compounds
Imaginary calculus
See under Calculus.
Imaginary expression [or] quantity
an algebraic expression which involves the impossible operation of taking the square root of a negative quantity; as, √-9, a + b √-1.
Imaginary points, lines, surfaces,
points, lines, surfaces, etc., imagined to exist, although by reason of certain changes of a figure they have in fact ceased to have a real existence.

Imaginary

n.
  1. An imaginary expression or quantity. (Alg.)