fermium

 
Pronunciation: /ˈfəːmɪəm/

noun

[mass noun]
  • the chemical element of atomic number 100, a radioactive metal of the actinide series. Fermium does not occur naturally and was discovered in 1953 in the debris of the first hydrogen bomb explosion. (Symbol: Fm)

Origin:

1950s: from the name of Fermi, Enrico + -ium