yttrium yttrious • yttrocerite · · · Info · Definitions · Synonyms · Characters · · yttrium · · Text Latin · · Script 7 · · Length Definitions · · · (noun) a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys. Synonyms: Y, atomic number 39. · · Noun Definition 1 Synonyms · · · y · · Synonym 1 atomic number 39 · · Synonym 2 Characters · · i latin small letter i U+0069 m latin small letter m U+006D r latin small letter r U+0072 t latin small letter t U+0074 u latin small letter u U+0075 y latin small letter y U+0079