A whole number above 1 that can not be made by multiplying other whole numbers.
Example: 5 is a prime number. We cannot multiply 2, 3 or 4 together to make 5. (Only 1×5 works but we said to use other whole numbers.)
Example: 6 can be made by 2 × 3 so is NOT a prime number (it is a composite number).
All whole numbers above 1 are either composite or prime.