Synesthesia
"The word “synesthesia” or “synaesthesia,” has its origin in the Greek roots, syn, meaning union, and aesthesis, meaning sensation: a union of the senses" (Allen-Hermanson). Synesthesia is usually used in Poetry. In Poetry it means "The concurrent response of two or more of the senses to the stimulation of one" (Harmon). It also means the mixing of two or more senses at one time.
Functions of Synesthesia
Writers tend to use this to give their writing more meaning. It gives writers the extra boost of creativity and description. Synesthesia makes writing more interesting and appealing to an audience.