Also aqua regis. [L.; = royal water.] A mixture of nitric and hydrochloric acids, so called because it can dissolve the ‘noble’ metals, gold and platinum.
1610. B. Jonson, Alch., II. v. What’s cohobation? ’Tis the pouring on Your aqua regis, and then drawing him off.
1641. French, Distill., iii. (1651), 70. Aqua regia, or Stygia … will dissolve Gold.
1869. Roscoe, Elem. Chem., 275. Gold trichloride, obtained when gold is dissolved in aqua regia.
