agreement vs promise

agreement

noun
  • An understanding between entities to follow a specific course of conduct. 

  • Rules that exist in many languages that force some parts of a sentence to be used or inflected differently depending on certain attributes of other parts. 

  • A legally binding contract enforceable in a court of law. 

  • A state whereby several parties share a view or opinion; the state of not contradicting one another. 

promise

noun
  • A placeholder object representing the eventual result of an asynchronous operation. 

  • A transaction between two persons whereby the first person undertakes in the future to render some service or gift to the second person or devotes something valuable now and here to his use. 

  • Reason to expect improvement or success; potential. 

  • an oath or affirmation; a vow 

verb
  • To commit to (some action or outcome), or to assure (a person) of such commitment; to make an oath or vow. 

  • To give grounds for expectation, especially of something good. 

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