.via Inky Fool:
She smelled the way the Taj Mahal looks by moonlight.
(- The Little Sister by Raymond Chandler)
Synaethesia is either a mental condition whereby colours are perceived as smells, smells as sounds, sounds as tastes etc, or it is a rhetorical device whereby one sense is described in terms of another. If colours are harmonious, or a voice is silky, that is synaesthesia (or some other spelling).
It is a common enough device, except that there seem to be rules, or norms governing which senses can be coupled. Sight and sound are interchangeable. Quite aside from John Lennon's request to George Martin that the orchestration of Strawberry Fields should be "orange", colours can be loud or discordant while melodies can be bright and rumblings dark. Tone is even an ambiguous word that can be applied to either sense, and I thoroughly recommend Ernest Bloch's Sketches in Sepia. (I omit colours that are purely symbolic: blues music is no more blue than blue movies are).
read entire article here: http://inkyfool.blogspot.com/2010/04/synaesthesia.html