Based on the word part meanings which term refers to the membrane between the outermost and innermost part of the heart endocardium mesocardium myocardium?

The term "mesocardium" refers to the membrane between the outermost and innermost parts of the heart. The prefix "meso-" means "middle," indicating its position between the outer layers (like the epicardium) and the innermost layer (the endocardium). In contrast, the endocardium refers specifically to the innermost layer, and myocardium refers to the muscular middle layer of the heart.