Meaning of uranium series

ura'nium se"ries

Pronunciation: (yoo-rā'nē-um-rā'dē-um). [key]
— Chem. Chem.
  1. the radioactive series that starts with uranium 238 and ends with a stable isotope of lead of mass number 206.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.