Nickel n. : A bright silver-white metallic element. 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 58.6.

Nickel n. : A small coin made of or containing nickel; esp., a five-cent piece.

Example:
How much Nickel is mined for one hybrid car battery?

Taxonomy
nickel, metal, alloys, copper, elements, coins, deposits, half-life, carbon monoxide, mineral, isotope, plating, 11-19, kJ, nickel compounds, compound, nickel carbonyl, nickel metal.

Defination from the web:
... Similar to the elements chromium, aluminium and titanium, nickel is a very reactive element, but is slow to react in air at normal temperatures ...