In mathematics, sexy primes are prime numbers that differ from each other by six. For example, the numbers 5 and 11 are both sexy primes, because they differ by 6. If p + 2 or p + 4 (where p is the lower prime) is also prime, then the sexy prime is part of a prime triplet.
The term "sexy prime" stems from the Latin word for six: sex.
n. (context mathematics English) Either of a pair of prime numbers that differ by six