adjective Physics, Chemistry.
- of, pertaining to, exhibiting, or caused by radioactivity.
adjective
- exhibiting, using, or concerned with radioactivity
1898, from French radio-actif, coined by Pierre and Marie Curie from radio-, comb. form of Latin radius (see radiation) + actif “active” (see active).
adj.
- Of or exhibiting radioactivity.
A descriptive term for a material made up of atoms in which radioactivity occurs.