Definition of ruthenium in US English:



  • The chemical element of atomic number 44, a hard silvery-white metal of the transition series.

    • ‘To this group belong the important steel alloying elements nickel and manganese, as well as cobalt and the inert metals ruthenium, rhodium, palladium, osmium, iridium and platinum.’
    • ‘Zirconium, palladium, and ruthenium make up a metal that repairs itself.’
    • ‘It is also classified with a group of similar metals, including ruthenium, rhodium, palladium, osmium, and iridium, with similar properties.’
    • ‘Along with ruthenium, rhodium, osmium, iridium, and platinum, it belongs to the platinum group of metals.’
    • ‘That porous layer, which contains stabilized zirconia and small amounts of the metals ruthenium and cerium, chemically and cleanly converts the fuel to hydrogen.’


Mid 19th century: modern Latin, from medieval Latin Ruthenia (see Ruthenia), so named because it was discovered in ores from the Urals.