* Muriatic acid: This is the common name for a concentrated aqueous solution of hydrogen chloride.

* Hydrochloric acid: This is the official name for the aqueous solution of hydrogen chloride.

* Spirit of salt: This is an older name for hydrochloric acid.

* HCl: This is the chemical formula for hydrogen chloride.

* Hydrogen monochloride: This is a less common systematic name.

It's important to note that the name used can depend on the context and the specific form of the compound. For example, "hydrogen chloride" usually refers to the gas, while "hydrochloric acid" refers to the aqueous solution.