1.
Radiation consists of very small particles of a radioactive substance. Large amounts of ~ can cause illness and death.
They suffer from health problems and fear the long term effects of ~...
N-UNCOUNT: also N in pl, oft N n
2.
Radiation is energy, especially heat, that comes from a particular source.
The satellite will study energy ~ from stars.
N-UNCOUNT: also N in pl, usu with supp