airline flight code for Air Mauritanie
• magnetic resonance (as in MR scanner )
• Computing magneto-resistive (as in MR heads )
• British fishing port registration for Manchester
• map reference
• Law Master of the Rolls
• match rifle
• (or M/R) Commerce mate's receipt
• mental retardation
• metabolic rate
• Middlesex Regiment
• Minister Residentiary
• motivation(al) research
• motorways (traffic) regulations
• municipal reform
• British vehicle registration for Swindon