imaginary

Etymology

From Middle English ymaginarie, ymagynary, from Latin imāginārius (“relating to images, fancied”), from imāgō. 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.

adj

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

noun

1. Imagination; fancy.
   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. 2002, Colin Jones, The Great Nation, Penguin, published 2003, page 324
2. (mathematics) An imaginary number.
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.
   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 […]. 1978, John Derrickson McCurdy, Visionary Appropriation, page 145
   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. 1994, Graham Dawson, Soldier Heroes: British Adventure, Empire, and the Imagining ..., page 51
   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 a 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. 2015, Adrian Daub, Elisabeth Krimmer, Goethe Yearbook 22, page 96