1. **Problem:** What is the definition of a "prime number"? 2. **Formula/Rule:** A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 3. **Explanation:** Prime numbers are the building blocks of all natural numbers because every number can be factored into primes. 4. **Intermediate Work:** For example, 7 is prime because its only divisors are 1 and 7. 5. **Final Answer:** A prime number is a number greater than 1 with exactly two distinct positive divisors: 1 and itself. This is the first question of 10 on basic terminologies in mathematics.