A twin prime is a pair of prime numbers that have a difference of two. For example, the numbers 3 and 5 are twin primes, as are 11 and 13. Prime numbers are those greater than one that have no divisors other than 1 and themselves. Twin primes are interesting in number theory because they are relatively rare compared to other prime numbers. The concept of twin primes is part of a larger study in mathematics known as the twin prime conjecture. This conjecture suggests that there are infinitely many twin primes, but it has not yet been proven. Mathematicians continue to explore the properties and distribution of twin primes in the field of number theory.