Synaesthesia (rhetorical device)
Synaesthesia is a rhetorical device or figure of speech where one sense is described in terms of another. This may often take the form of a simile. One can distinguish the literary joining of terms derived from the vocabularies of sensory domains from synaesthesia as a neuropsychological phenomenon. Panchronistic tendencies. It has been suggested that, in the tradition of Romantic poetry, the sensory transfer consisting in the synaesthesic metaphor tends to be from a lower (less differentiated) sense to a higher sense. In this respect, the sequence of senses from low to high is generally taken to  be touch, taste, smell, sound, then sight. This observation was named a panchronistic tendency by Stephen Ullmann since he saw the lowest levels of sense having the poorest vocabulary. Upwards transfers are thought to have strong emotional effects, but downwards transfers generally witty effects. Rhetorical synaesthesia as simile. Examples of synaesthesic simile: Rhetorical synaesthesia as transmodal modification. When a modifier which would normally apply to one sense is used collocating a noun evocative of another sense, this is known as transmodal modification. Examples include: Rhetorical synaesthesia as transmodal predication. When a noun evoking one sense is linked with a predicate  evoking another, this is known as transmodal predication. Examples include: Synaesthetic polysemy. When a linkage of two senses depends upon a pun, this is known as synaesthetic polysemy. Examples include: