A composite number is a positive integer that has at least one positive divisor other than one and itself. This means that composite numbers can be divided evenly by numbers other than just 1 and the number itself. For example, the number 4 is composite because it can be divided by 1, 2, and 4.
In contrast, a prime number has exactly two distinct positive divisors: 1 and the number itself. The smallest composite number is 4, and other examples include 6, 8, and 9. Understanding composite numbers is essential in number theory and helps in various mathematical applications.