isorhythmic Syllabification: (i·so·rhyth·mic)Pronunciation: /ˌīsəˈriT͟Hmik/Definition of isorhythmic adjective Music (of a composition or part) in which the rhythm is often repeated but the pitch of the notes is varied each time. isorhythmic in other Oxford dictionaries Definition of isorhythmic in the British & World English dictionary