R4, R04, R.4, R-4, or R/4 may refer to:
Military
Aircraft
- Caudron R.4, World War I French reconnaissance aircraft, first flown in 1915
- Curtiss R-4, air ambulance version of the American Curtiss Model R utility aircraft, first flown in 1915
- Sikorsky R-4, American helicopter, first flown in 1942
Ships
- HMCS Cayuga (R04), Royal Canadian Navy destroyer
- USS R-4 (SS-81), U.S. Navy submarine
Weapons
- R4 assault rifle, produced by South African manufacturer Vektor
- Remington R4 carbine, assault rifle used by the Philippine Marine Corps
- Bisnovat R-4, Soviet missile
Other military
- Plan R 4, the World War II British plan for an invasion of the neutral state of Norway in April 1940
Science
- R4, designation of risk phrase "Forms very sensitive explosive metallic compounds"
- R4 nuclear reactor, the fourth nuclear reactor built in Sweden
- Exotic R, in mathematics, a differentiable manifold
Transportation
Cars
- R4, abbreviation for rear-engine, four-wheel drive layout
- R4, a sub-class of Group R rally cars
- Jaguar R4, Jaguar Racing's car for the 2003 Formula One season
- McRae R4, a rally car designed in part by Colin McRae
- Renault R4, alternative name for the Renault 4
- Suzuki GSX-R/4, a concept car made by Suzuki in 2001
Roads
- R4 ring road in Ghent, Belgium
- R4 expressway (Czech Republic)
- R4 expressway (Slovakia)
- R-4 motorway (Spain)
- R4 road (Zimbabwe), a road connecting Harare and Nyamapanda
- Radial Road 4 or R-4, an arterial road of Manila, Philippines
Other transportation
- R4 (Canberra), a bus route in Canberra, Australia
- R4 (New York City Subway car)
- R4 (RER Vaud), an S-Bahn line in the canton of Vaud
- R4 (Rodalies de Catalunya), a commuter rail line in Barcelona, Catalonia, Spain
- R4 41st Avenue RapidBus, an express bus service in Vancouver, BC, Canada
Video games
- R4: Ridge Racer Type 4, a racing game for Sony PlayStation, developed by Namco
- Rush Rush Rally Racing, a racing game for Sega Dreamcast, developed by Senile Team
- R4 cartridge, a Nintendo DS flash cartridge
Other uses
- BBC Radio 4 the premier BBC speech radio station
- R4, a building in the Norwegian Government quarter (Norw. Regjeringskvartalet)
- Region 4, the DVD region code for most of Mexico, Central America, South America, Australia, New Zealand, Oceania
See also
Topics referred to by the same termThis disambiguation page lists articles associated with the same title formed as a letter–number combination.If an internal link led you here, you may wish to change the link to point directly to the intended article. Category: