Definitions of attorney in fact
a person who is authorized to perform certain acts for another person based on a power of attorney
He authorised his daughter, as his attorney in fact, to withdraw money from the bank on his behalf.
someone, who may or may not be a lawyer, named by another through a written power of attorney (=a written authorization for a person to act on behalf of another person) to do a specific act or to conduct business in general for that person
I have been appointed and am currently serving as the attorney-in- fact for the above referenced individual pursuant to the validity executed power of attorney attached hereto.