RUTHENIUM

ruthenium, Ru, atomic number

(noun) a rare polyvalent metallic element of the platinum group; it is found associated with platinum

Source: WordNet® 3.1

Etymology

Ruthenia + -ium

Noun

ruthenium (countable and uncountable, plural rutheniums)

A metallic chemical element (symbol Ru) with an atomic number of 44.

(countable) An atom of this element.

Source: Wiktionary

Ru*the"ni*um, n. Etym: [NL. So named from the Ruthenians, a Little Russian people, as coming from Russia, the metal having been found in the Ural mountains.] (Chem.)

Definition: A rare element of the light platinum group, found associated with platinum ores, and isolated as a hard, brittle steel-gray metal which is very infusible. Symbol Ru. Atomic weight 103.5. Specific gravity 12.26. See Platinum metals, under Platinum.

Source: Webster’s Unabridged Dictionary 1913 Edition