We don't have synonyms for polyrhythms yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are polyrhythm and polyrhythmic.
(n) :
(uncountable, music) Music with multiple rhythmic elements played simultaneously.
(n) :
(countable, music) A rhythm or set of rhythms performed as part of a piece of music with multiple rhythmic elements played simultaneously, typically equally spaced in time and coprime.
(n) :
(countable, music) Music containing such a rhythm.
(n) :
(uncountable, music) Music with multiple rhythmic elements played simultaneously.
(n) :
(countable, music) A rhythm or set of rhythms performed as part of a piece of music with multiple rhythmic elements played simultaneously, typically equally spaced in time and coprime.
(n) :
(countable, music) Music containing such a rhythm.