fibromyalgia Syllabification: (fi·bro·my·al·gia)Pronunciation: /ˌfībrōmīˈalj(ē)ə/Definition of fibromyalgia noun a chronic disorder characterized by widespread musculoskeletal pain, fatigue, and tenderness in localized areas. fibromyalgia in other Oxford dictionaries Definition of fibromyalgia in the British & World English dictionary