The Collaborative International Dictionary of English v.0.48:

Nickel \Nick"el\, n. [G., fr. Sw. nickel, abbrev. from Sw.
   kopparnickel copper-nickel, a name given in derision, as it
   was thought to be a base ore of copper. The origin of the
   second part of the word is uncertain. Cf. Kupfer-nickel,
   Copper-nickel.]
   1. (Chem.) A bright silver-white metallic element of atomic
      number 28. It is of the iron group, and is hard,
      malleable, and ductile. It occurs combined with sulphur in
      millerite, with arsenic in the mineral niccolite, and with
      arsenic and sulphur in nickel glance. Symbol Ni. Atomic
      weight 58.70.
      [1913 Webster]

   Note: On account of its permanence in air and inertness to
         oxidation, it is used in the smaller coins, for plating
         iron, brass, etc., for chemical apparatus, and in
         certain alloys, as german silver. It is magnetic, and
         is very frequently accompanied by cobalt, both being
         found in meteoric iron.
         [1913 Webster]

   2. A small coin made of or containing nickel; esp., a
      five-cent piece. [Colloq. U.S.]
      [1913 Webster]

   Nickel silver, an alloy of nickel, copper, and zinc; --
      usually called german silver; called also argentan.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Argentan \Ar"gen*tan\, n.
   An alloy of nickel with copper and zinc; German silver.
   [1913 Webster]