Jern is the Danish word for "iron," a chemical element with the symbol Fe and atomic number 26. It is a metal that is known for its strength and durability, making it a vital material in construction and manufacturing. Iron is commonly used to produce steel, which is an alloy that enhances its properties for various applications. Iron is abundant in the Earth's crust and is primarily extracted from ores such as hematite and magnetite. It plays a crucial role in various biological processes, including the transport of oxygen in the blood through hemoglobin. Its versatility and importance make it one of the most widely used metals in the world.