1.NounA belief or tenet, especially about philosophical or theological matters.
"The Incarnation is a basic doctrine of Christianity.; The Four Noble Truths summarise the main doctrines of Buddhism."
2.NounThe body of teachings of an ideology, most often a religion, or of an ideological or religious leader, organization, group, or text.
"What is the understanding of marriage and family in orthodox Marxist doctrine?"
3.NounA 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 Monroe Doctrine the Brezhnev Doctrine the Negroponte Doctrine"