noun A superficial structure of dead tissue, usually hardened, and commonly but not necessarily dark, adhering to underlying living or necrotic tissue, caused by gangrene or a burn.
noun Any hard, dark, commonly flattened or sunken lesion or crust, especially on a burn, abscess, infection, wound; commonly a coagulation of blood or exudations, not necessarily involving dead or necrotic tissue.
noun The emotional imprint of a trauma such as grief, loss, or degradation.