Synesthesia is a neurological condition in which two or more perceptions (sometimes including the senses) mix. Each type of synesthesia executes cross–perception one way only and not the other. For instance, I have sight–to–sound synesthesia and although I hear sound with my eyes, I do not see vision with my ears. I would have to have additional type of synesthesia in order to see with my ears. . Synesthetic perceptions are just as adequate as any normal perception, seeing that perceptions are just the brain taking in stimulus and interpreting them into what it understands: a synesthete's (person with synesthesia's) brain just understands certain stimulus differently than most brains would. This implies that synesthetes are not necessarily insane and their perceptions are just as real as anyone else's. . Put simply, Synesthesia is blended perception.
The production of a sense impression relating to one sense or part of the body by stimulation of another sense or part of the body. The poetic description of a sense impression in terms of another sense, as in “a loud perfume.”.