neptunium
Concise Oxford English Dictionary © 2008 Oxford University Press:
neptunium /nɛpˈtjuːnɪəm/
▶noun the chemical element of atomic number 93, a radioactive metal of the actinide series. (Symbol: Np)
– origin C19: from Neptune, on the pattern of uranium (Neptune being the next planet beyond Uranus).
'neptunium' also found in these Oxford entries:
