R3, R.III or R-3 or R/3 may refer to: Aviation Aviatik R.III, a German aircraft DFW R.III, a World War I German bomber aircraft Ross R-3 glider Tupolev R-3 Soviet reconnaissance aircraft Yakutia Airlines IATA airline designator Entertainment BBC Radio 3, a radio operated by the BBC within the United Kingdom R3 (TV series), produced by the BBC between 1964 and 1965 Region 3, the DVD region code for Southeast Asia, South Korea, Republic of China (Taiwan), Hong Kong, Macau Resistance 3, the third game in the Resistance series R3 (video game), a computer game for the Amiga series of computers in 1995 Military Version of the German Rheintochter ground to air missile R-3 (missile), the Vympel K-13, an air-to-air missile also known as R-3S in Soviet service R-3 (tank), a proposed Romanian tank design for use in World War II USS R-3 (SS-80), a 1919 R-class coastal and harbor defense submarine of the United States Navy Math and Science R3: Extreme risk of explosion by shock, friction, fire or other sources of ignition, a risk phrase in chemistry R-3 process, a chromogenic photo process for making Type R prints R3 or receptor 3, the third in line of a series of cellular receptors, generally at the end of an acronym R3, three-dimensional space, the Euclidean space of real numbers in three dimensions Transportation R3 expressway (Czech Republic), a road connecting Kaplice and the border with Austria R3 expressway (Slovakia), a road connecting Krupina and Zvolen Radial Road 3 or R-3, an arterial road of Manila, Philippines R-3 motorway (Spain), a road connecting Madrid and Tarancón R3 (SEPTA), a former commuter rail line in and near Philadelphia, Pennsylvania, which has been split into: Media/Wawa Line (R3 Media/Elwyn, formerly R3 West Chester), West Trenton Line (SEPTA) (R3 West Trenton) R3 (ring road) in Belgium R3 (Rodalies de Catalunya), a commuter rail line in Barcelona, Catalonia, Spain R3 Lougheed Highway, an express bus route in Metro Vancouver, British Columbia, Canada Other uses Ågestaverket, also known as R3, was the third nuclear reactor built in Sweden Jaguar R3, a car made by Jaguar Racing for the 2002 Formula One season Leica R3, a 1976 35mm SLR camera Reduce, reuse, recycle SAP R/3, the previous designation for an enterprise resource planning software produced by SAP AG; the new name is SAP ERP Yamaha R3 ISO Recommendation R3, a forerunner to the international standard ISO