thorium vs radiothorium

thorium and radiothorium both are nouns.

Word	Noun	Adjective	Verb	Adverb
thorium	Yes	No	No	No
radiothorium	Yes	No	No	No

As nouns, radiothorium is a hyponym of thorium; that is, radiothorium is a word with a more specific, narrower meaning than thorium:

thorium: a soft silvery-white tetravalent radioactive metallic element; isotope 232 is used as a power source in nuclear reactors; occurs in thorite and in monazite sands
radiothorium: radioactive isotope of thorium with mass number 228

Other hyponyms of thorium include thorium-228.

thorium (noun)	radiothorium (noun)
a soft silvery-white tetravalent radioactive metallic element; isotope 232 is used as a power source in nuclear reactors; occurs in thorite and in monazite sands	radioactive isotope of thorium with mass number 228