Advance health care directive
An instrument that allows an adult to appoint one or more others to make certain health care decisions on behalf of the adult. The adult who creates the advance health care directive is often called the “declarant.” The one or more other adults appointed by the declarant are often called “agents.” Although all States recognize one or more instruments for delegating health care decision-making authority, the terms and rules vary. For example, the term “advance health care directive” may be shortened to “advance directive” or may be interchangeable with other terms like “medical power of attorney,” “power of attorney for health care,” or “health care proxy.” In some States, the term “advance directive” is an umbrella term that includes both a medical power of attorney and a “living will”.
Agent
A second person appointed by a first person through a legal instrument to make certain decisions, such as medical or financial decisions, on behalf of the first person. An agent appointed through an advance health care directive would have authority to make certain health care decisions, while an agent appointed through a financial power of attorney would have authority to make certain financial decisions. An agent appointed through a power of attorney may sometimes also be called an “attorney-in-fact.”
Alternatives to Guardianship
These are tools other than guardianship that people can use to get the support they need to make tough decisions about their lives.
Assignment of rights
An instrument where an adult student voluntarily authorizes another person to make educational decisions on the student’s behalf, in the same way the student’s parent would have done so while the student was a minor. Only a minority of States’ educational regulations or statutes recognize this instrument. Some States refer to this instrument as a “delegation” instead.
Declarant
The term commonly used for the person who appoints a health care agent through an advance health care directive or other similar instrument, such as a power of attorney for health care.
Educational representative
A person appointed to make educational decisions on behalf of an adult student receiving special education services under the Individuals with Disabilities Education Act who has been determined to be unable to provide informed consent for decisions. Only a minority of States’ educational regulations or statutes describe a formal process for making these determinations and they vary across States.
Execute
The act of completing an instrument, by which time the creator of the instrument must have completed all the steps required by State law for the instrument to be legally enforceable.
Fiduciary
A term that describes the special responsibility that a person has towards the creator of an instrument. Generally, a person with a fiduciary relationship to another has a duty to put the other person’s interests ahead of the person’s own. So, even if one person has transferred decision-making authority to a second person, the second person does not have complete discretion to exercise that authority. Instead, the second person must exercise that authority in a way that clearly benefits the first person. For example, an agent appointed by a power of attorney generally has a fiduciary duty to the principal.
Guardianship
Guardianship is a legal term. Guardianship is when a court decides that a person cannot make their own decisions. The court then gives someone else (a guardian) the power to make decisions for the person.  
Incapacity
A status that may trigger decision-making authority to transfer from one person to another. Definitions of “incapacity” and the rules for determining it vary widely across States. Some States use various other terms instead, such as “incompetent” or “incapacitated” or “incapable” of making decisions or managing one’s affairs. Note that some State laws use the term “disability” as interchangeable with “incapacity.”
Instrument
The formal name for a tool, generally a written document or a completed form signed by the instrument’s creator, that creates a legal arrangement, such as an advance health care directive, power of attorney, or supported decision-making agreement.
Living will
A type of advance directive that does not appoint a health care agent but describes a person’s preferences or wishes for the kinds of health care or medical treatment they will receive in the future if the person is determined incapable of making those decisions.
Power of attorney
An instrument that allows an adult to appoint one or more others to make certain decisions on behalf of the adult. All States recognize powers of attorney for financial decisions, and many have adopted the terms of the Uniform Powers of Attorney Act, which is a common set of rules for powers of attorney developed by the Uniform Law Commission. In some States, powers of attorney may be used for other types of decisions as well, including educational decisions.
Principal
The person who creates an instrument, such as a power of attorney, that appoints one or more other persons to exercise decision-making authority on that person’s behalf.
Supported decision-making agreement
An instrument that allows an adult to formally recognize the ways in which the adult wishes to be assisted in making certain decisions by others. Unlike an advance health care directive or power of attorney, a supported decision-making agreement generally does not transfer decision-making rights from one person to another. Only a minority of States have statutes recognizing supported decision-making agreements.