fibrocystic Syllabification: (fi·bro·cys·tic)Pronunciation: /ˌfībrəˈsistik, ˌfib-/Definition of fibrocystic adjective [attributive] Medicine (of a disease) characterized by the development of fibrous tissue and cystic spaces, typically in the pancreas or the breast. fibrocystic in other Oxford dictionaries Definition of fibrocystic in the British & World English dictionary