atomic number 90

Từ điển WordNet v3.1 - WordNet Dictionary

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
• Syn:
thorium, Th
• Derivationally related forms:
thoriate (for: thorium)
• Hypernyms:
metallic element, metal
• Hyponyms:
thorium-228, radiothorium
• Substance Holonyms:
monazite, thorite