Pronunciation: (rā"dē-ō-kär'bun), [key]
1. Also called carbon 14. a radioactive isotope of carbon with mass number 14 and a half-life of about 5730 years: widely used in the dating of organic materials.
2. any radioactive isotope of carbon.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.