ra·di·o·i·so·tope 
(rā′dē-ō-īsə-tōp′)
(rā′dē-ō-īsə-tōp′)n.
A naturally or artificially produced radioactive isotope of an element.
- inoffensive
- inoffensively
- inoffensiveness
- in on
- in one ear and out the other
- in one fell swoop
- in one same breath
- in (one's) blood
- in one's blood
- in (one's) bones
- in one's bones
- in (one's) book
- in one's book
- in (one's) cups
- in one's cups
- in (one's) heart of hearts
- in one's heart of hearts
- in (one's) own right
- in one's own right
- in (one's) pocket
- in one's pocket
- in (one's) tracks
- in one's tracks
- in (one's) wheelhouse
- in one's wheelhouse