doctrine vs theology

doctrine

noun
  • A belief or tenet, especially about philosophical or theological matters. 

  • A self-imposed policy governing some aspect of a country's foreign relations, especially regarding what sort of behavior it will or will not tolerate from other countries. 

  • The body of teachings of an ideology, most often a religion, or of an ideological or religious leader, organization, group, or text. 

theology

noun
  • A particular belief within a religion. 

  • Synonym of religious studies 

  • Subjective marginal details. 

  • An organized method of interpreting spiritual works and beliefs into practical form. 

  • The study of God, a god, or gods; and of the truthfulness of religion in general. 

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