Radioactive material

Definition:

Material that contains unstable (radioactive) atoms that give off [ionizing] radiation as they decay.

Source: CDC Glossary of Radiological Terms  

Related words:

Caesium - Countdown 2010 - Iodine - Radiation - Radioactivity - Strontium-90

To read about this term in context:

GreenFacts Summary on the Chernobyl Nuclear Accident:

Translation(s):

Español: Material Radiactivo
Français: Substance radioactive

Related publications: