radioactive isotope
n.
An isotope having an unstable nucleus that decomposes spontaneously by emission of a nuclear electron or helium nucleus and radiation, thus achieving a stable nuclear composition.
Words nearby radioactive isotope
rectovaginal septum,
rectovesical muscle,
rectovesical pouch,
rectovesical septum,
rectrix,
radioactive isotope,
rectus,
recumbent,
recumbent bicycle,
recuperate,
recuperative