synesthesia

Noun

synaesthesia (countable and uncountable, plural synaesthesiae or synaesthesias)

1. A neurological or psychological phenomenon whereby a particular sensory stimulus triggers a second kind of sensation.
   • M. [Théodore] Flournoy includes all the phenomena of "Colored Hearing" and of "Mental Forms" under the convenient and adequate name Synæsthesia—in place of which, to be sure, he himself usually employs the less defensible term Synopsie. […] The phenomena of synæsthesia are divided into three main...1893 July, Mary Whiton Calkins, “De Phénomènes de Synopsie. Par Th. Flournoy. Paris, Alean, 1893. [book review]”, in G[ranville] Stanley Hall, editor, The American Journal of Psychology, volume V...
2. (broadly) The association of one sensory perception with, or description of it in terms of, a different perception that is not experienced at the same time.
   • On a phonemic level, phenomena of synesthesia have often been described and studied. Practically all children and a good many adults—though for the most part adults will deny it—spontaneously associate sounds, whether phonemes or the timbre of musical instruments, with colors and forms.1963, Claude Lévi–Strauss, “Postscript to Chapters III and IV”, in Claire Jacobson, Brooke Grundfest Schoepf, transl., Structural Anthropology: Translated from the French (Harper Torchbooks; TB5017)...
3. A literary or artistic device whereby one kind of sensation is described in the terms of another.
   • Linking moods with colours is one example of synaesthesia. […] As a tool for improving writing, the idea of synaesthesia is versatile and innovative. Why use only visual references to describe visual impressions? Why just describe sounds using sound-related words? Play with cross-matching the...2006, Stephen Bowkett, “Descriptive Writing”, in Boys and Writing (Pocket PAL), London: Network Continuum Education, Continuum International Publishing Group, →ISBN, page 38