Argon is a chemical element, a colourless gas with the symbol Ar. It is in the air around you. Learner dictionaries sometimes call the amount “very small,” though actually argon makes up close to one percent of the air — far more than the other noble gases, and much more than carbon dioxide. What is small is how little it does: it almost never joins in chemical reactions, which is why it was named from a Greek word for idle or lazy. That quietness is useful. It is put inside some electric light bulbs, and people use it when they weld metal, because it will not burn or spoil the work. It belongs with neon and the other noble gases.