R

nouns

a unit of radiation exposure; the dose of ionizing radiation that will produce 1 electrostatic unit of electricity in 1 cc of dry air
R, roentgen
(physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole
R, gas constant, universal gas constant
the 18th letter of the Roman alphabet
R, r