Search Result：atomic number 90
atomic number 90 
(TTS Sound)
(TTS Sound)Overview of noun atomic_number_90
The noun atomic number 90 has 1 sense
- thorium, Th, atomic number 90 -- (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)