Definition of R (symbol)

R (symbol): This much-used symbol has many meanings in medicine. They include:

1. Respiration: a nurse's note of "R20" is shorthand for 20 respirations (breaths) per minute.
2. Right: A doctor's note of a burn on the "R digit 5" places the burn on the right little finger or toe.
3. Roentgen, an international unit of X-radiation or gamma-radiation.
4. In chemistry, a radical.
5. On a prescription, R (or Rx), recipe, which is Latin for "to take".