Definition of nickel
1
: a silver-white hard malleable ductile metallic element capable of a high polish and resistant to corrosion that is used chiefly in alloys and as a catalyst — see Chemical Elements Table
2 a (1)
: the U.S. 5-cent piece regularly containing 25 percent nickel and 75 percent copper
(2)
: the Canadian 5-cent piece
b
: five cents
3
slang
: a packet containing five dollars worth of an illicit drug (such as marijuana) — called also
nickel bag
4
: a pass defense in football that employs five defensive backs
