obligation vs power of attorney

obligation

noun
  • The act of binding oneself by a social, legal, or moral tie to someone. 

  • A social, legal, or moral requirement, duty, contract, or promise that compels someone to follow or avoid a particular course of action. 

  • A course of action imposed by society, law, or conscience by which someone is bound or restricted. 

  • A legal agreement stipulating a specified action or forbearance by a party to the agreement; the document containing such agreement. 

  • The fact of being obliged to, that is, grateful for, something. 

power of attorney

noun
  • A legal document allowing one person to act as the agent of another. 

  • The legal authorisation of one person to act as the agent of another. 

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