X2

X2 may refer to:

X2 (Chipset), the standard chipset for 56k downstream modem communications
X2 (film), a 2003 American movie also known as X-Men United
X2 Turntable, a turntable manufactured by Numark
X2 train, used for X2000 train system in Sweden
Athlon 64 X2, the first dual-core desktop CPU manufactured by AMD
Bell X-2, an experimental supersonic aircraft
X2, a video game
Final Fantasy X-2, another video game
Megaman X2, another video game
Skycycle X-2, the rocket used by Evel Knievel in his attempt to cross the Snake River Canyon in 1974
Bathyscaphe Trieste II, also known as X-2, the US Navy bathyscaphe based on the Trieste
SpaceShipOne flight 17P, also known as "X2", the second Ansari X Prize flight
XXX: State of the Union, also known as X2 or XXX², a 2005 American film

Additionally, X² may refer to:

X²: The Threat, a video game
Square (algebra), also known as the "algebraic square", a concept in algebra
Chi-square distribution, a theoretical probability distribution widely used in inferential statistics