Synaesthesia

From the Ancient Greek σύν (syn), “together,” and αἴσθησις (aisthēsis), synaesthesia is a neurologically based phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.  People who experience this fusion of sense are known as synesthetes.

syn·aes·the·sia /ˌsɪnəsˈθiʒə, -ʒiə, -ziə/ Show Spelled Pronunciation [sin-uhs-thee-zhuh]

– noun

1. A sensation produced in one modality when a stimulus is applied to another modality.
2. A condition in which one type of stimulation evokes the sensation of another, as when the hearing of a sound produces the visualization of a color.
3. The description of one kind of sense impression by using words that normally describe another.

syn·aes·thet’ic /ˌsɪnɪsˈθɛtɪk/ Show Spelled Pronunciation [sin-is-thet-ik]

– /ˌsɪnɪsˈθɛtɪk/ Show Spelled Pronunciation adjective

1. involving more than one sense.