A more thorough explanation:

Definition: A canon is a fundamental rule or principle that is widely accepted.

Examples:

• The scientific method is a canon in the field of science.
• The Constitution is a canon in the United States legal system.
• The Bible is a canon in Christianity.

The examples illustrate how a canon is a widely accepted principle or rule in a particular field or system. The scientific method is a fundamental rule that scientists follow to conduct experiments and make discoveries. The Constitution is a fundamental rule that governs the United States legal system. The Bible is a fundamental rule that guides the beliefs and practices of Christians.