Diamorphine is a powerful pain-relieving drug that is also known as heroin. However, there are various synonyms for diamorphine which are used interchangeably depending on the country and the context in which the drug is used. Some of the commonly used synonyms for diamorphine include morphine diacetate, diacetylmorphine, dicodeine, and diamide. Other names used for diamorphine include street names such as H, horse, smack, and junk. Moreover, the drug is sometimes referred to as white horse depending on the purity level and the method of administration. Despite these names and synonyms, it is important to note that diamorphine is an illegal substance that can pose serious health risks and addiction problems if abused.