Explain the usage of principle and principal.

The words "principle" and "principal" are often confused due to their similar spellings and pronunciations. However, they have different meanings and usage in the English language.

1. Principle:
- "Principle" is a noun that refers to a fundamental truth, law, or belief that serves as the foundation for a system of thought or behavior. It represents a guiding concept or moral standard.
- It can also refer to a basic truth or rule that is used as a basis for reasoning or decision-making.
- Examples:
- "Honesty is a principle that should be upheld in all aspects of life."
- "The principle of supply and demand governs the market economy."
- "She refused to compromise her principles, even in difficult situations."

2. Principal:
- "Principal" can be used as both a noun and an adjective.
- As a noun, it refers to the head or leader of a school or organization. It can also refer to the main participant or actor in a situation.
- As an adjective, it describes something that is primary, main, or most important.
- Examples:
- "The principal of the school addressed the students during the assembly."
- "The principal amount of the loan needs to be repaid within five years."
- "She played the principal role in the movie."

To differentiate between the two words, it is important to remember that "principle" relates to fundamental beliefs or rules, while "principal" refers to a person in a leadership position or something that is primary or most important.