We don't have synonyms for synaesthesias yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are synesthesia, synaesthesia and synesthesias.
(n) :
(neurology, psychology) A neurological or psychological phenomenon whereby a particular sensory stimulus triggers a second kind of sensation.
(n) :
(by extension) The association of one sensory perception with, or description of it in terms of, a different perception that is not experienced at the same time.
(n) :
(art, literature) A literary or artistic device whereby one kind of sensation is described in the terms of another.
(n) :
(neurology, psychology) A neurological or psychological phenomenon whereby a particular sensory stimulus triggers a second kind of sensation.
(n) :
(by extension) The association of one sensory perception with, or description of it in terms of, a different perception that is not experienced at the same time.
(n) :
(art, literature) A literary or artistic device whereby one kind of sensation is described in the terms of another.