Nitrohydrochloric Acid, commonly known as aqua regia, is a highly corrosive and reactive mixture of concentrated nitric acid and hydrochloric acid. It is used for dissolving noble metals like gold and platinum, as it can dissolve even the most inert metals. There are few synonyms for Nitrohydrochloric Acid which are used interchangeably. Some of these synonyms for Nitrohydrochloric Acid include Royal Water, Spirit of Salt, and King's Water. The term "Royal Water" describes its ability to dissolve gold and the term "Spirit of Salt" has been used for centuries to describe hydrochloric acid. Overall, these synonyms are widely used in scientific research and industrial processes where the acid is utilized.