A Power of Attorney is an instrument which authorizes one person to act as another's agent or attorney-in-fact. The attorney-in-fact need not actually be a licensed attorney. The Power of Attorney may be for a performance of a specific, definite act or duty, or it may be general in nature. It may be for a specific time period or for an indefinite time period. It may be revocable. If not revoked, it usually expires when the person granting the Power of Attorney dies. A Power of Attorney may grant the attorney-in-fact authority to convey or mortgage real estate. If this is so in your state, the Power of Attorney must be written, signed and otherwise executed like a deed. It should be recorded to put others on notice as to the powers of the attorney-in-fact. Please see specific state for details and/or differences.

Black's Law Dictionary, Fifth Edition.