lithium Syllabification: (lith·i·um)Pronunciation: /ˈliTHēəm/Definition of lithium noun the chemical element of atomic number 3, a soft silver-white metal. It is the lightest of the alkali metals. (Symbol: Li) lithium carbonate or another lithium salt, used as a mood-stabilizing drug. Origin: early 19th century: from lithia + -iumlithium in other Oxford dictionaries Definition of lithium in the British & World English dictionary
