The six degrees of separation hypothesis is the idea that any two people on Earth are connected by a maximum of six mutual acquaintances. The concept is based on the notion of a social network, where individuals are linked to each other by some type of relationship, such as friendship, family, work, or other similar connections. According to this theory, it would be possible for any two strangers to be linked by a series of acquaintances, with each person in the sequence knowing the next one in the chain until the final connection is made.

The term "six degrees of separation" was popularized by the 1993 movie of the same name, starring Will Smith. The concept was originally introduced in a 1929 short story by Hungarian author Frigyes Karinthy, titled "Chains." Over time, the idea of six degrees of separation has been studied and debated, and while it may not always hold true in practice, it does highlight the interconnectedness of the modern world and the potential for social networks to bridge distances and connect individuals.