1. A radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gases; occurs naturally (especially in areas over granite) and is considered a hazard to health
   - radon, atomic number 86

1. A graduate nurse who has passed examinations for registration
   "The RN administered the medication according to protocol";
   - registered nurse

Type of: argonon, inert gas, noble gas, nurse, sister [Brit]

Encyclopedia: Rn