Power of Attorney:
A power of attorney (POA) or letter of attorney is a written authorization to represent or act on another's behalf in private affairs, business, or some other legal matter, sometimes against the wishes of the other. The person authorizing the other to act is the principal, grantor, or donor (of the power). The one authorized to act is the agent or, in some common law jurisdictions, the attorney-in-fact (attorney for short).
Durable Power of Attorney:
Under the common law, a power of attorney becomes ineffective if its grantor dies or becomes "incapacitated," meaning unable to grant such a power, because of physical injury or mental illness, for example, unless the grantor (or principal) specifies that the power of attorney will continue to be effective even if the grantor becomes incapacitated. This type of power of attorney is called "power of attorney with durable provisions" in the United States or "enduring power of attorney" elsewhere. In effect, under a durable power of attorney (DPA), the authority of the attorney-in-fact to act and/or make decisions on behalf of the grantor continues until the grantor’s death.
Healthcare Power of Attorney:
In some jurisdictions, a durable power of attorney can also be a "health care power of attorney." This particular affidavit gives the attorney-in-fact the authority to make health-care decisions for the grantor, up to and including terminating care and life support. The grantor can typically modify or restrict the powers of the agent to make end-of-life decisions. In many jurisdictions a health care power of attorney is also referred to as a "health care proxy" and, as such, the two terms are sometimes used interchangeably.