atomic number 61 atomic number 60 • atomic number 62 · · · Info · Definitions · Synonyms · Characters · · atomic number 61 · · Text Common · · Latin · · Scripts 16 · · Length 8 · · Syllables Definitions · · · (noun) a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium. Synonyms: promethium, Pm, atomic number 61. · · Noun Definition 1 Synonyms · · · promethium · · Synonym 1 pm · · Synonym 2 Characters · · space U+0020 1 digit one U+0031 6 digit six U+0036 a latin small letter a U+0061 b latin small letter b U+0062 c latin small letter c U+0063 e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 t latin small letter t U+0074 u latin small letter u U+0075