noun. An alloy of aluminum that contains copper, manganese, magnesium, iron, and silicon and is resistant to corrosion by acids and seawater.

proper noun. an aluminum-based alloy which is both light and strong, containing 4 per cent of copper and 0.5 per cent of magnesium and smaller amounts of iron, manganese, and silicon. It hardens with aging at room temperature.

noun. an alloy of over 90% aluminium, 4% copper and traces of manganese, magnesium, iron and silicon, widely used in the aircraft industry

noun. an aluminum-based alloy

"The framework was made of a new alloy called 'duralumin', nearly as strong in tension as mild steel and not much heavier than aluminium."