declaration vs oath

declaration

noun
  • A written or oral indication of a fact, opinion, intention, belief, etc. 

  • In common law, the formal document specifying plaintiff's cause of action, including the facts necessary to sustain a proper cause of action, and to advise the defendant of the grounds upon which he is being sued. 

  • The specification of an object, such as a variable or function, establishing its existence but not necessarily describing its contents. 

  • The act, by the captain of a batting side, of declaring an innings closed. 

  • The act or process of declaring. 

  • A list of items for various legal purposes, e.g. customs declaration. 

oath

noun
  • A solemn pledge or promise that invokes a deity, a ruler, or another entity (not necessarily present) to attest the truth of a statement or sincerity of one's desire to fulfill a contract or promise. 

  • A light, irreverent or insulting appeal to a deity or other entity. 

  • A curse, a curse word. 

  • A statement or promise which is strengthened (affirmed) by such a pledge. 

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