principle >> /ˈprɪnsəpəl/
Definition: [noun] A fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning.
Example: the basic principles of Christianity
Definition: [noun] A general scientific theorem or law that has numerous special applications across a wide field.
Example: Physics has a big advantage here, since the ability to derive interesting conclusions from general principles comes earlier in physics than in other sciences.
Definition: [noun] A fundamental source or basis of something.