imaginary (English)

Where does "imaginary" come from?

The English adjective 'imaginary' comes from Middle English 'ymaginarie'[1], which derives from the Latin 'imāginārius', meaning 'relating to images, fancied'[1]. The Latin form itself stems from 'imāgō'[1], tracing back to the Proto-Indo-European root '*h₂eym-', meaning 'to imitate'[3]. The mathematical sense of the word emerged in 1637 when René Descartes used the French 'imaginaire' to disparage non-real polynomial roots, and this designation persisted even after the concept gained acceptance during the eighteenth century[1].

Open questions

• The Proto-Indo-European root *h2eym- is reconstructed as meaning to imitate or copy. [3] [4]

Full etymology tree

• imaginary (English), 'Existing only in the imagination.'
  • inherited ymaginarie (Middle English)
    • borrowed imaginarius (Latin), 'image'
      • suffix imago (Latin), 'image, imitation, likeness, statue, representation'
        • suffix *imā (Proto-Italic), 'copy'
          • derived *h₂éymō (Proto-Indo-European), 'imitation'
        • suffix -ago (Latin), 'Suffixed to nouns, forms nouns describing objects, plants, and animals.'
      • suffix -arius (Latin), 'Used to form adjectives from nouns or numerals.'
  • influenced by imaginaire (French), 'imaginary (created by and existing only in the imagination)'
    • learned borrowing imaginarius (Latin), 'image'
      • suffix imago (Latin), 'image, imitation, likeness, statue, representation'
        • suffix *imā (Proto-Italic), 'copy'
          • derived *h₂éymō (Proto-Indo-European), 'imitation'
        • suffix -ago (Latin), 'Suffixed to nouns, forms nouns describing objects, plants, and animals.'
      • suffix -arius (Latin), 'Used to form adjectives from nouns or numerals.'

Ancestors

• imaginarius (Latin)

Descendants and derived words

• imaginarily (English)
• imaginariness (English)
• imaginarity (English)
• imaginary axis (English)
• imaginary friend (English)
• imaginary geometry (English)
• imaginary lat syndrome (English)
• imaginary museum (English)
• imaginary number (English)
• imaginary part (English)
• imaginary time (English)
• imaginary unit (English)

Related words

• fantasy (English)
• hallucination (English)

Sources

1. imaginary (English) - Wiktionary
2. imaginarius (Latin) - Wiktionary
3. imago (Latin) - Wiktionary
4. imā (Proto-Italic) - Wiktionary
5. imaginaire (French) - Wiktionary

Updated October 2026

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Etymology data from Wiktionary, CC BY-SA 4.0 · About Miraris