If something is charred, it has been burned until it is black. Toast can be charred; a tree after a fire is charred; meat on a grill can be charred on purpose, because some cooks like that bitter black edge. It is stronger and blacker than “toasted” or “browned.” The thing is often still there, just black and dry — not fully gone to ash. It sits next to charcoal, the black fuel made when wood is burned in a careful way.