There are no strict rules in Wikipedia, as it is not a bureaucracy. However in order to describe best practice, clarify principles, resolve conflicts and otherwise further our goal of creating a free, reliable encyclopedia, the community has developed some policies and guidelines. These policies and guidelines have not been carved in stone, they're open for discussion.
- Policies explain and describe standards that all users should normally follow.
- Guidelines are meant to outline best practices for following those standards in specific contexts.
- Essays are usually the opinion or advice of an editor or group of editors, sometimes as a means of summarising existing policies and sometimes as suggested guidelines for which widespread consensus has not been established. Thus two contradicting essays might exist at the same time.
- Principle is a more encompassing word, including policies, guidelines, essays and other principles, such as the founding principles of Wikimedia.
- Policies and guidelines should always be applied using reason and common sense. The principles and spirit of Wikipedia's rules matter more than their literal wording, and sometimes improving Wikipedia requires making an exception to a rule.