Definition of aqua regia in US English:

aqua regia


  • A mixture of concentrated nitric and hydrochloric acids. It is a highly corrosive liquid that will dissolve gold and other resistant substances.

    • ‘His method had two key innovations: he used aqua regia with the most effective molar ratio of hydrochloric to nitric acids; and the amount of aqua regia used was sufficient to dissolve only about half of the crude ore.’
    • ‘Gold also resists attack by most acids but is soluble in aqua regia, a mixture of three parts hydrochloric acid and one part nitric acid.’
    • ‘It is not attacked by most acids, although it does dissolve in aqua regia (a mixture of concentrated nitric acid and 3-4 parts of hydrochloric acid).’
    • ‘Some time before 1300, sulfuric acid was prepared, and alchemists created aqua regia, a mixture of sulfuric and nitric acids that is capable of dissolving gold, platinum, and many other materials.’
    • ‘Gold resists corrosion by air and most chemicals but can be dissolved in a mixture of nitric and hydrochloric acids, a solution called aqua regia because it dissolves the ‘king of metals’.’


Early 17th century: Latin, literally ‘royal water’.