The conflation of the senses, such as when we refer to a color as "loud" (mixing sight and sound) or a scent as "sharp" (mixing smell and touch). Poets sometimes use synesthesia to striking effect, as ???.

From the Guide to Literary Terms by Jack Lynch.
Please send comments to Jack Lynch.
Note: This guide is still in the early stages of development.
Three question marks mean I have to write more on the subject. Bear with me.