teaching, principle, position, or belief established within a belief system, school of thought, or academic discipline

Doctrine (Latin: doctrina) is a code of beliefs or "a body of teachings".

English Wiktionary
English Wiktionary
The English Wiktionary has a dictionary definition (meanings of a word) for: doctrine

Doctrine often means several religious dogmas that a church teaches. But it can also mean a principle of law, in the common law traditions, established through a history of past decisions, such as the doctrine of self-defense, or the principle of fair use.

In matters of foreign policy, a doctrine, also known as dogma, is group of fundamental rules for a nation's foreign policy. Examples include the Monroe Doctrine, the Stimson Doctrine, the Truman Doctrine, the Eisenhower Doctrine, the Nixon Doctrine, the Brezhnev Doctrine, the Kirkpatrick doctrine, and the Bush Doctrine.

Religious usage change

Examples of religious doctrines include:

One department of the Roman Curia is called the Congregation for the Doctrine of the Faith.

Military usage change

The term also applies to the concept of an established procedure to a complex operation in warfare. The typical example is tactical doctrine in which a standard set of maneuvers, kinds of troops and weapons are employed as a default approach to a kind of attack.

Examples of military doctrines include: