myxoma Syllabification: (myx·o·ma)Pronunciation: /mikˈsōmə/Definition of myxoma noun (plural myxomas or myxomata /-mətə/) Medicine a benign tumor of connective tissue containing mucous or gelatinous material. Derivatives myxomatousPronunciation: /-mətəs/ adjective myxoma in other Oxford dictionaries Definition of myxoma in the British & World English dictionary