DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   R
       n 1: a unit of radiation exposure; the dose of ionizing
            radiation that will produce 1 electrostatic unit of
            electricity in 1 cc of dry air [syn: roentgen, R]
       2: (physics) the universal constant in the gas equation:
          pressure times volume = R times temperature; equal to 8.3143
          joules per kelvin per mole [syn: gas constant, universal
    gas constant, R]
       3: the 18th letter of the Roman alphabet [syn: R, r]
       4: the length of a line segment between the center and
          circumference of a circle or sphere [syn: radius, r]