rhenium Rhenish • rheobase · · · Info · Definitions · Synonyms · Characters · · rhenium · · Text Latin · · Script 7 · · Length Definitions · · · (noun) a rare heavy polyvalent metallic element that resembles manganese chemically and is used in some alloys; is obtained as a by-product in refining molybdenum. Synonyms: Re, atomic number 75. · · Noun Definition 1 Synonyms · · · re · · Synonym 1 atomic number 75 · · Synonym 2 Characters · · e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E r latin small letter r U+0072 u latin small letter u U+0075