Source : Webster's Revised Unabridged Dictionary (1913)

Electrum \E*lec"trum\, n. [L., fr. Gr. ?. See {Electric}, and
   cf. {Electre}, {Electron}.]
   1. Amber.

   2. An alloy of gold and silver, of an amber color, used by
      the ancients.

   3. German-silver plate. See {German silver}, under {German}.

Source : WordNet®

electrum
     n : an alloy of gold and silver