fermium fermion • fermorite · · · Info · Definitions · Synonyms · Characters · · fermium · · Text Latin · · Script 7 · · Length 3 · · Syllables Definitions · · · (noun) a radioactive transuranic metallic element produced by bombarding plutonium with neutrons. Synonyms: Fm, atomic number 100. · · Noun Definition 1 Synonyms · · · fm · · Synonym 1 atomic number 100 · · Synonym 2 Characters · · e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 m latin small letter m U+006D r latin small letter r U+0072 u latin small letter u U+0075