As a fundamental truth or belief:
* The principle of democracy is based on the idea that all people have equal rights.
* He lived his life by the principles of honesty and integrity.
* The company's principles of sustainability are outlined in their mission statement.
As a rule or law:
* The principle of physics that governs gravity is fundamental to understanding the universe.
* The principle of supply and demand dictates prices in the market.
* She used the principle of least resistance to approach the problem.
As a fundamental element:
* The principle of the machine is quite simple.
* The principle of this design is to maximize space.
* He explained the basic principles of accounting to his students.
In a formal or legal context:
* The judge ruled in favor of the plaintiff based on the principle of precedent.
* The new law was based on the principle of equity.
* The company's operations were based on the principles outlined in its charter.
In a figurative sense:
* The principle of the matter is that you need to take responsibility for your actions.
* She stood on her principles and refused to compromise.
* He wouldn't betray his principles even under pressure.