|the offspring of a zebra and a donkey.|
|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
radioisotope ra·di·o·i·so·tope (rā'dē-ō-ī'sə-tōp')
A naturally or artificially produced radioactive isotope.
|radioisotope (rā'dē-ō-ī'sə-tōp') Pronunciation Key
A radioactive isotope of a chemical element. Carbon 14 and radon 222 are examples of naturally occurring radioactive isotopes.