nobelium Syllabification: (no·bel·i·um)Pronunciation: /nōˈbelēəm/Definition of nobelium noun the chemical element of atomic number 102, a radioactive metal of the actinide series. Nobelium does not occur naturally and was first produced by bombarding curium with carbon nuclei. (Symbol: No)Origin: 1950s: modern Latin, from the name Nobel, Alfred Bernhard + -iumnobelium in other Oxford dictionaries Definition of nobelium in the British & World English dictionary