R21
R21 stands for:
- HMAS Melbourne (R21) , a light aircraft carrier for the Royal Australian Navy
- Renault 21 , a car made by Renault
- R21 (Gabon) , regional road in Gabon
- R21 (Russia) , a trunk road
- R21 (computer) , a DDR mainframe computer from Robotron from the 1970s
R-21 stands for:
- a refrigerant, see dichlorofluoromethane
- a Soviet missile, see R-21 (missile)
