imaginary

Meaning

Adj

1. Existing only in the imagination.
2. Having no real part; that part of a complex number which is a multiple of √ (called imaginary unit).
3. Having no real part; that part of a complex number which is a multiple of √ (called imaginary unit).

Noun

1. Imagination; fancy.
2. (countable) An imaginary number.
3. The set of values, institutions, laws, and symbols common to a particular social group and the corresponding society through which people imagine their social whole.

Synonyms

fictitious

fanciful

fantastic

unreal

fictional

notional

imaginary number

hypothetical

ideal

chimeric

romantic

fantastical

imaginative

chimerical

fictive

visionary

make-believe

whimsical

complex number

complex quantity

nonexistent

fancied

invented

imagination

imagined

imitation

insubstantial

absent

made-up

mental

mock

mythical

phantom

plasmatic

pretend

priggish

sham

spurious

supposed

toy

unsubstantial

untrue

vaporous

veridical

pseudo-

literary

abstract

artificial

assumed

conceited

Translations

imaginaire

imaginario

immaginario

imaginär

imaginário

φανταστικός

eingebildet

imaginair

denkbeeldig

hayali

fictief

vorgestellt

imaginari

fictif

fiktiv

Pronounced as (IPA)

/ɪˈmæd͡ʒɪnəɹi/

Etymology

Inherited from Middle English: ymaginarie

In summary

From Middle English ymaginarie, ymagynary, from Latin imāginārius (“relating to images, fancied”), from imāgō, equivalent to imagine + -ary.
The mathematical sense derives from René Descartes's use (of the French imaginaire) in 1637, La Geometrie, to ridicule the notion of regarding non-real roots of polynomials as numbers. Although Descartes' usage was derogatory, the designation stuck even after the concept gained acceptance in the 18th century.