A type of power of attorney. A power of attorney is a legal document that gives one person (such as a relative, lawyer, or friend) the authority to make legal, medical, or financial decisions for another person. It may go into effect right away, or when that person is no longer able to make decisions for himself or herself. A durable power of attorney remains in effect until the person who grants it dies or cancels it. It does not need to be renewed over time. Also called DPA.