perimysium
noun
peri·my·si·um ˌper-ə-ˈmi-zhē-əm 
-zē-
plural perimysia ˌper-ə-ˈmi-zhē-ə
-zē-
: the connective-tissue sheath that surrounds a muscle and forms sheaths for the bundles of muscle fibers
Word History
Etymology
New Latin, irregular from peri- + Greek mys mouse, muscle — more at mouse entry 1
First Known Use
circa 1842, in the meaning defined above
Medical Definition
perimysium
noun
peri·my·si·um ˌper-ə-ˈmiz(h)-ē-əm
plural perimysia -ē-ə
: the connective-tissue sheath that surrounds a muscle and forms sheaths for the bundles of muscle fibers