R2

R2, R02, R.II, R.2 or R-2 may refer to:

Entertainment

• R2: Reign of Revolution, an online game
• R2 (Rock'n'Reel), a British music magazine
• R2-D2, a character from Star Wars films and books
  • R2 unit, a line of droids in the fictional Star Wars universe
• Code Geass: Lelouch of the Rebellion R2, a 2008 anime series
• Resistance 2, a video game
• Relapse 2, a 2009 album by rapper Eminem
• Patricio Rey y sus Redonditos de Ricota or R2, an Argentine rock band

Science

• R², a symbol for the coefficient of determination of a linear regression
• R², the two-dimensional vector space of real numbers in mathematics
• R2: Risk of explosion by shock, friction, fire or other sources of ignition, a risk phrase in chemistry
• R2 RNA element, a cis-acting element identified in R2 retrotransposons which is involved in priming the reverse transcription process
• ATC code R02 Throat preparations, a section of the Anatomical Therapeutic Chemical Classification System
• Haplogroup R2 (Y-DNA), a human Y-chromosome haplogroup
• receptor 2, the second in line of a series of cellular receptors, generally at the end of an acronym
• Robonaut 2, a humanoid robotic development project conducted by the Dextrous Robotics Laboratory, deployed on the International Space Station

Computing

• .r02, a RAR file extension
• Windows Server 2003 R2
• Windows Server 2008 R2

Transportation

• R2 (SEPTA)
  • Wilmington/Newark Line (R2 Wilmington/Newark line)
  • Warminster Line (R2 Warminster line)
• Autopista Radial R-2, a Spanish radial motorway connecting Madrid to Guadalajara and passing through Alcobendas and connecting to N-320
• R2 expressway (Slovakia)
• Orenburg Airlines by IATA code

Vehicles

• DFW R.II, a 1918 German bomber aircraft
• Fiat R.2, a 1919 Italian reconnaissance aircraft
• HMS Zest (R02), a World War II British Royal Navy Z-class destroyer
• Jaguar R2, Jaguar Racing's car for the 2001 Formula One season
• Linke-Hofmann R.II, a World War I German bomber aircraft
• Panzer 35(t), a Czech tank whose Romanian model was known as the R-2.
• Polikarpov R-2, a Soviet Union copy of the 1931 British Airco DH.9A light bomber aircraft
• Ross R-2 Ibis glider
• Subaru R2, a 2003 Japanese car
• USS R-2 (SS-79), a 1918 R-class coastal and harbor defense submarine of the United States Navy

Other

• R-2 (missile), an improved version of German V-2 rocket manufactured by the Soviet Union
• R2 signalling, a family of telephony protocols for line and register signalling
• BBC Radio 2, a British radio station
• DVD region code 2
• Region 2, the DVD region code for Europe (except Russia, Ukraine, and Belarus), Middle East, Egypt, Japan, South Africa, Swaziland, Lesotho, Greenland
• Gangrene ICD-10 code
• A version of NASA's Robonaut