epimysium Syllabification: (ep·i·my·si·um)Pronunciation: /ˌepəˈmizēəm, -ˈmiZHēəm/Definition of epimysium noun Anatomy a sheath of fibrous elastic tissue surrounding a muscle. Origin:modern Latin, from epi- 'upon' + Greek mus 'muscle'epimysium in other Oxford dictionaries Definition of epimysium in the British & World English dictionary