endocardium development
The process whose specific outcome is the progression of the endocardium over time, from its formation to the mature structure. The endocardium is an anatomical structure comprised of an endothelium and an extracellular matrix that forms the innermost layer of tissue of the heart, and lines the heart chambers.
GO:0160108
animal gross anatomical part developmental process
is_a
GO:0007507
heart development
part_of