What is Advance Directive?

Legal Definition
A legal document that takes effect if one cannot make decisions due to illness or incapacity. Different types of advance directives exist. Some, such a living will, give instructions on which measures can be used to prolong life. Others simply name a surrogate decision-maker for medical questions.
Legal Definition
A document about final wishes of an individual. It is drawn up in case the person becomes unable to make their own decisions. AKA living will.