arbiter vs attorney-in-fact

arbiter

noun
  • A person or object having the power of judging and determining, or ordaining, without control; one whose power of deciding and governing is not limited. 

  • A person appointed, or chosen, by parties to determine a controversy between them; an arbitrator. 

  • A component in circuitry that allocates scarce resources. 

verb
  • To act as arbiter. 

attorney-in-fact

noun
  • An agent of the person giving him/her the power of attorney (for a specific purpose or for general purposes) to act on his or her behalf. The attorney-in-fact’s power and responsibilities depend on the specific powers granted in the power of attorney document. 

How often have the words arbiter and attorney-in-fact occurred in a corpus of books? (source: Google Ngram Viewer )