myopathy Syllabification: (my·op·a·thy)Pronunciation: /mīˈäpəTHē/Definition of myopathy noun (plural myopathies) Medicine a disease of muscle tissue. Derivatives myopathicPronunciation: /ˌmīəˈpaTHik/ adjective myopathy in other Oxford dictionaries Definition of myopathy in the British & World English dictionary