Muriaticum is a chemical compound consisting of hydrogen and chloride ions. It is known by many synonyms, including hydrogen chloride, hydrochloric acid, chlorohydric acid, and spirits of salt. They are all used interchangeably to describe the same chemical compound, but each term has its unique context and usage. Hydrogen chloride is mostly used in the laboratory setting when discussing the gas form. Hydrochloric acid is commonly used in industrial processes, such as pickling and etching metals. Spirits of salt is the historical term for hydrochloric acid, and chlorohydric acid is seldom used in modern chemical terminology. Despite the different synonyms, they all refer to the same basic chemical compound, each with its specific applications.