gadoliniumEnglishOxford Dictionary of Englishgadolinium /ˌɡadəˈlɪniəm , ˌɡadlˈɪniəm / ▸ noun [mass noun] (Symbol: Gd) the chemical element of atomic number 64, a soft silvery-white metal of the lanthanide series. – ORIGIN late 19th century: from gadolinite.