Etymologically
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imaginary

This is the current revision of this entry, as edited by bogdan on 22 October 2026 at 21:33. This address is a permanent link to this version.
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Pronunciation

  • UK: /ɪˈmæd͡ʒɪnəɹi/, /ɪˈmæd͡ʒɪnɹi/[1]
  • US: /ɪˈmæd͡ʒɪˌn(ɛ)ɹi/[1]

Etymology

It is borrowed from Latin imāginārius (“consisting of a mere semblance, unreal, fictitious”),[2][3][4] formed with the suffix -ārius (English -ary) on imāgō (“image”).[2][5][6] In post-classical Latin the adjective also meant "concerning images" (early 4th century) and "of the imagination" (from the 12th century in British sources), and as a noun it named a standard-bearer (4th century).[2] Etymonline also allows that it may have been formed in English from imagine and -ary.[7] Johnson (1755) gave its source as imaginaire.[8]

Earliest recorded meaning

Existing only in imagination or fancy; not real: a1425, in the later version of the Wycliffite Bible.[2] Etymonline dates imaginarie to the late 14th century, and Dictionary.com to 1350–1400.[7][6]

Semantic evolution

Early senses also included "existing only as spirit, not bodily", now obsolete.[2] From 1541 the word described a line or circle assumed to pass through certain points but otherwise not existing.[2][4] Several 16th- and 17th-century senses died out: of the nature of an image (1594–1671, first in Shakespeare's Lucrece), imaginable (1624–1862), and supposed, putative (a1631–1803).[2][9] Johnson (1755) defined it as "fancied; visionary; existing only in the imagination".[8] In mathematics Isaac Newton used it in 1670 for a quantity expressed through the square root of a negative number,[2] and the noun imaginary, such a quantity, follows in 1768.[2] The noun had earlier meant a Roman officer who carried the emperor's image (a1460) and a fancy, something imagined (1594).[2] Imaginary friend is attested by 1789.[7]

Timeline

  • a1425 – existing only in the imagination.[2]
  • a1460 – noun, an officer who carried the emperor's image (obsolete).[2]
  • 1541 – of a line or circle, assumed but not physically real.[2]
  • 1594 – noun, something imagined.[2]
  • 1670 – (mathematics) involving the square root of a negative quantity.[2]
  • 1768 – noun, (mathematics) an imaginary quantity.[2]
  • 1789 – imaginary friend.[7]

Modern meaning

Adjective

  1. Existing only in the imagination; not real: The child chatted away to an imaginary companion.
  2. Of a line or point, assumed for the purposes of description but having no physical existence: an imaginary line between the two peaks.
  3. (mathematics) Involving or being an imaginary number, a multiple of the square root of −1.

Noun

  1. (mathematics) An imaginary quantity or complex number.

Word family

  • imaginarily
  • imaginariness
  • imaginary number
  • imaginary unit

Usage notes

Dictionary.com lists imaginative as a word often confused with imaginary.[6]

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  4. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  5. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
  6. ^ a b c Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
  7. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  8. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  9. ^ Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)