thorium-228 vs Th

thorium-228 and Th both are nouns.

Word	Noun	Adjective	Verb	Adverb
thorium-228	Yes	No	No	No
Th	Yes	No	No	No

As nouns, Th is a hypernym of thorium-228; that is, Th is a word with a broader meaning than thorium-228:

thorium-228: radioactive isotope of thorium with mass number 228
Th: 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

Other hypernyms of thorium-228 include atomic number 90, thorium.

thorium-228 (noun)	Th (noun)
radioactive isotope of thorium with mass number 228	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
	the fifth day of the week; the fourth working day