myocardium
noun
myo·car·di·um ˌmī-ə-ˈkär-dē-əm 
: the middle muscular layer of the heart wall
myocardial
ˌmī-ə-ˈkär-dē-əl
adjective 
Example Sentences
Recent Examples on the Web Myocarditis is inflammation of the myocardium, the muscles in the heart, according to Medline Plus. 
Korin Miller, Health.com, 26 Apr. 2021 Hemorrhagic softening of the myocardium, liver, kidneys and spleen. Dawn Mitchell, Indianapolis Star, 2 Aug. 2019
Korin Miller, Health.com, 26 Apr. 2021 Hemorrhagic softening of the myocardium, liver, kidneys and spleen. Dawn Mitchell, Indianapolis Star, 2 Aug. 2019 Word History
Etymology
New Latin, from my- + Greek kardia heart — more at heart
First Known Use
1879, in the meaning defined above
Medical Definition
myocardium
noun
myo·car·di·um ˌmī-ə-ˈkärd-ē-əm
plural myocardia -ē-ə
: the middle muscular layer of the heart wall