Mustard gases, also known as sulfur mustard, are a type of poisonous gas used as a chemical weapon. These gases cause severe skin burns, blisters, respiratory problems and even death. To avoid confusion and repetition in writing or speaking, it is important to know some synonyms for this term. Some of the synonyms for mustard gases are HD, yperite, bis-(2-chloroethyl) sulfide, and sulfur mustard. Although these terms refer to the same type of gas, the use of synonyms can help to provide clarity and variety in communication. It is essential to know these synonyms in order to understand and recognize the severity of these weapons.