Six degrees
Six degrees of separation is the theory that anyone on Earth can be connected to any other person on the planet through a chain of acquaintances that has no more than five intermediaries
Six degrees or  Six degrees of separation may also refer to:

Six degrees of freedom, motion in three-dimensional space, with three translation motions (up/down, left/right, forward/back) and three rotation motions (yaw, pitch, roll)
Six Degrees of Kevin Bacon, a trivia game that requires a group of players to connect any film actor to Kevin Bacon in as few links as possible
SixDegrees.org, a social networking website created by Bacon based on the game, intended to link people to charities
SixDegrees.com, a social networking website from 1997 to 2001
Six Degrees patent, covering patterns on which modern social networking is founded
Six Degrees Architects, an Australian architectural firm in Melbourne, Victoria

Books
Six Degrees: The Science of a Connected Age, a science book by Duncan J. Watts, covering the application of network theory to sociology
Six Degrees: Our Future on a Hotter Planet, 2007 book by Mark Lynas, about the impact each single degree increase in temperature could have on our planet over the next century
SixDegrees (magazine), English-language Finnish magazine

Film, television, and drama
Six Degrees (TV series), aka 6°, a 2006 American television series that aired on ABC
6Degrees, aka Six Degrees, a 2012–2015 British/Northern Irish television series that aired on BBC-NI
Six Degrees of Separation (play), a play by American playwright John Guare
Six Degrees of Separation (film), a 1993 American film adaptation of the Guare play
"Six Degrees of Separation" (Battlestar Galactica), an episode of the television series Battlestar Galactica
Six Degrees of Separation from Lilia Cuntapay, a Philippine independent film
Lonely Planet Six Degrees, an American travel television program

Music
"Six Degrees of Separation" (song), a song by Irish rock band The Script from their album #3
Six Degrees of Inner Turbulence, a full-length studio album by progressive metal band Dream Theater
"Six Degrees of Inner Turbulence" (song), the title track of the aforementioned album
Six Degrees Records, a recording company noted for its catalog of recordings from international musicians and vocalists