ep·i·mys·i·um 
(ĕp′ə-mĭzē-əm, -mĭzhē-)
(ĕp′ə-mĭzē-əm, -mĭzhē-)n. pl. ep·i·mys·i·a (-mĭzē-ə, -mĭzh-)
The external sheath of connective tissue surrounding a muscle.
[New Latin epimȳsium : EPI- + Greek mūs, muscle; see mūs- in the Appendix of Indo-European roots.]