imaginary

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.[1] Although Descartes' usage was derogatory, the designation stuck even after the concept gained acceptance in the 18th century.

• (Received Pronunciation) IPA^(key): /ɪˈmæd͡ʒɪnəɹi/, /ɪˈmæd͡ʒɪnɹi/
• (General American) IPA^(key): /ɪˈmæd͡ʒɪˌnɛɹi/

• Audio (GA)

  (file)

• Hyphenation: im‧a‧gin‧a‧ry

imaginary (comparative more imaginary, superlative most imaginary)

1. Existing only in the imagination.

   Unicorns are imaginary.

   • 1712 (date written), [Joseph] Addison, Cato, a Tragedy. […], London: […] J[acob] Tonson, […], published 1713, →OCLC, Act I, scene iv, page 1:

     Wilt thou add to all the griefs I suffer / Imaginary ills and fancied tortures?

2. (mathematics, of a number) Having no real part; that part of a complex number which is a multiple of ${\displaystyle {\sqrt {-1}}}$ (called imaginary unit).

• (existing only in the imagination): all in one's head

imaginary (plural imaginaries)

1. Imagination; fancy. [from 16th c.]
   • 2002, Colin Jones, The Great Nation, Penguin, published 2003, page 324:

     By then too Mozart's opera, from Da Ponte's libretto, had made Figaro a stock character in the European imaginary and set the whole Continent whistling Mozartian airs and chuckling at Figaresque humour.

2. (mathematics) An imaginary number. [from 18th c.]
3. (sociology) 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. [from c. 1975]
   • 1978, John Derrickson McCurdy, Visionary Appropriation, page 145:

     The sensory media are sensuous materials which prolong our bodily life into the surrounding world, and hence the media are imaginaries. These perceptually penetrated materials are " imaginaries " because they operate here in our living body […] .

   • 1994, Graham Dawson, Soldier Heroes: British Adventure, Empire, and the Imagining ..., page 51:

     For example, colonial motifs of many kinds became increasingly central to the British national imaginary from the mid-nineteenth century, while the imaginative significance of 'the soldier' has long been derived from, and helped to sustain, the linkage between national and military imaginaries.

   • 2015, Adrian Daub, Elisabeth Krimmer, Goethe Yearbook 22, page 96:

     While Oil, its extraction, and the global petroculture and its role in transforming the planet's climate undoubtedly play a crucial role in the Antropocene imaginary — to the extent that petrofiction has been construed not just as a genre but as a periodizing gesture of "petromodernity"  — it would hamper both the imagination and the root of petrofiction to restrict the range of this term to the encounter with fossil fuels within a carbon imaginary.