Biochem. , symbol for arginine
• Medieval Roman numeral for eighty
• (ital.) Chem. , symbol for molar gas constant
• Chem. , symbol for a radical (in formulae, as in ROH )
• symbol for radius
• British fishing port registration for Ramsgate
• symbol for rand (South African monetary unit)
• Maths. , symbol for ratio
• Physics , symbol for Réaumur (temperature scale)
• (ital.) Chem. rectus (as in (R)-butan-2-ol )
• Electrical engineering , symbol for resistance
• Chem. , symbol for resonance effect
• Films (Australia , USA ) restricted (certification)
• retarder (French: slow down; on a clock or watch regulator)
• return (ticket or fare)
• reverse (on selector mechanism of vehicle with automatic transmission)
• Physics , symbol for roentgen
• Chess , symbol for rook
• Microbiol. rough (in R-form of a bacterial colony)