A nickel is a US coin worth five cents, or one-twentieth of a dollar. Twenty nickels equal one dollar. Before 1866, the five-cent coin was much smaller and made of silver, but people called the new, larger coin a “nickel,” and the name stuck.

You might use nickels to buy a small snack from a vending machine or save them in a piggy bank. When someone says “not worth a plugged nickel,” they mean something is worthless. If you tell someone not to nickel and dime you, you're asking them to stop bothering you about tiny amounts of money.

The word nickel also refers to the silvery-white metal itself, which stays shiny and resists rust. Nickel is used in stainless steel, batteries, and protective coatings on other metals. Scientists use the symbol Ni for nickel on the periodic table.