What does the term 'non-ferrous metal' refer to?

The term 'non-ferrous metal' refers to metals that do not contain significant amounts of iron. This definition is important because non-ferrous metals, such as aluminum, copper, zinc, and lead, exhibit distinct properties compared to ferrous metals, which do contain iron and are typically more prone to rust and corrosion. Non-ferrous metals are often valued in various industries for their lightweight, resistance to corrosion, and high conductivity. Understanding this distinction is crucial in fields ranging from construction to manufacturing, as it informs material selection based on the desired characteristics for specific applications.

The other options do not accurately capture the definition of non-ferrous metals, focusing instead on elements that are either related to iron or are irrelevant to the actual categorization of metals.