Metal is a type of material that's typically hard, shiny, and excellent at conducting heat and electricity. Gold, silver, iron, copper, and aluminum are all metals. Most metals can be shaped by hammering or melting them down and pouring them into molds, which is why humans have used them for thousands of years to make everything from coins and jewelry to tools, bridges, and skyscrapers.

Metals have special properties that make them incredibly useful. They're strong and durable, so a metal ladder won't snap under your weight like a plastic one might. They conduct electricity, which is why the wires in your walls are made of copper. They also conduct heat, which is why cooking pots are metal: heat from the stove travels quickly through the metal to cook your food.

In nature, most metals don't exist in pure form. Instead, they're mixed with rock and other materials in substances called ores. Humans learned to extract metal from ore thousands of years ago by heating it in extremely hot fires, a process called smelting. The Bronze Age and Iron Age were named after the metals people learned to work with during those periods.

The word can also describe a style of rock music known for its loud, heavy sound and electric guitars, called heavy metal or just metal.