British vehicle registration for Luton
• radar operator (or observer)
• radio operator
• Radio Orchestra
• Psychol. reality orientation
• receiving office(r)
• receiving order
• record(s) office
• recruiting officer
• regimental order
• registered office
• relieving officer
• reserved occupation
• returning officer
• Chem. reverse osmosis
• symbol for rial Omani (monetary unit of Oman)
• international vehicle registration for Romania
• British fishing port registration for Rothesay
• airline flight code for Tarom-Romanian Air Transport