rüˈthēnēəm noun
( -s )
Etymology: New Latin, from Medieval Latin Ruthenia Russia, where it was first found + New Latin -ium
: a hard brittle grayish white polyvalent rare metallic element that is one of the platinum metals and resembles osmium but is more resistant to corrosion (as by oxidizing acids), that occurs in platinum ores especially in iridosmine, and that is used chiefly in hardening platinum and palladium alloys — symbol Ru ; see element table