fibroadenoma Syllabification: (fi·bro·ad·e·no·ma)Pronunciation: /ˌfībrōˌadnˈōmə/Definition of fibroadenoma noun (plural fibroadenomas or fibroadenomata /-adnˈōmətə/) Medicine a tumor formed of mixed fibrous and glandular tissue, typically occurring as a benign growth in the breast. fibroadenoma in other Oxford dictionaries Definition of fibroadenoma in the British & World English dictionary