rhenium(n = noun.substance) atomic number 75, re - 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;
rhenium, n. Chem. a rare metallic element of the manganese group, occurring naturally in molybdenum ores and used in the manufacture of superconducting alloys.