Etymograph

English

imaginary

Imaginary comes from Latin imāginārius ‘relating to images, fancied’, and goes back to Proto-Indo-European *h₂eym- ‘to imitate’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eym-1‘to imitate’reconstructed
  2. Latinc. 75 BCE–200 CEimāgō2‘image, imitation, likeness, statue, representation’
  3. Latinc. 75 BCE–200 CEimāginārius2‘relating to images, fancied’
  4. Middle Englishc. 1150–1500ymaginarie2
  5. Englishearliest quotation 1712imaginary2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin imago
  2. 2 Wiktionary, English imaginary
  3. Earliest quotation in Wiktionary’s entry: 1712, Joseph Addison, Cato: “Wilt thou add to all the griefs I suffer…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eym-Wiktionary, Latin imago‘to imitate’reconstructed
  2. Latinc. 75 BCE–200 CEimāgōWiktionary, English imaginary‘image, imitation, likeness, statue, representation’
  3. Latinc. 75 BCE–200 CEimāgināriusWiktionary, English imaginary‘relating to images, fancied’
  4. Middle Englishc. 1150–1500ymaginarieWiktionary, English imaginary
  5. Englishearliest quotation 1712imaginaryWiktionary, English imaginary. Earliest quotation in Wiktionary’s entry: 1712, Joseph Addison, Cato: “Wilt thou add to all the griefs I suffer…”

The story

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.

Full etymology on Wiktionary

Linked words

through Proto-Indo-European *h₂eym- ‘to imitate’

emulate, imitation, imitate, emulation, imitator, 8 more

through Latin imāgō ‘image, imitation, likeness, statue,…’

image, imago, 6 more

Today it means

adj Existing only in the imagination.

Sources

Sources: Wiktionary, “imaginary”; the older steps come from the Wiktionary entry for Latin imago. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Proto-Indo-European *h₂eym- / imaginary

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