nickel, Ni, atomic number 28 -- (a hard malleable ductile silvery metallic element that is resistant to corrosion; used in alloys; occurs in pentlandite and smaltite and garnierite and millerite)
nickel -- (a United States coin worth one twentieth of a dollar)
nickel, nickel note -- (five dollars worth of a drug; "a nickel bag of drugs"; "a nickel deck of heroin")