An iron is a device that is used for flattening out wrinkles in clothes. Irons have a handle at the top and a flat, smooth, metal bottom that is heated up. Once the bottom is hot it is rubbed over your clothes to smooth them out. Irons work better if the clothes are very slightly damp so many irons have a spray or steam feature. Old fashioned irons were made of solid metal, and you put them in a fire to heat them up. Modern irons are heated by electricity. Iron is also a type of metal.