Enter a clue or pattern or both:
The Clue
Part of a sac surrounding the heart (10 letter answer)
The Answer
EPICARDIUM
Tags
Notes
The answer EPICARDIUM is so rare that it appears less than once every 2500 puzzles.
Definition
EPICARDIUM as a noun:
1. (epicardium, visceral pericardium) = the innermost of the two layers of the pericardium