Every synesthetic pairing has two halves: the inducer that triggers it and the concurrent that is experienced. In chromesthesia the inducer is sound; in grapheme-color synesthesia it is a letter or numeral.
Forms of synesthesia are named inducer first, concurrent second, so “lexical-gustatory” means words in, tastes out. Inducers can be surprisingly abstract: not just raw sensations but concepts like weekdays or personalities of numbers, which is one line of evidence behind the broader framing of ideasthesia.
Audio-reactive visual software borrows the structure directly: an audio feature acts as inducer, a visual parameter as concurrent, with the mapping designed rather than innate.