Acyl chloride is a compound that is commonly used in chemical industries. It is a reactive and corrosive substance that is extensively used in the synthesis of various pharmaceuticals and agrochemicals. Some of the synonyms for acyl chloride are acid chloride, acyl halide, acyl bromide, and acyl fluoride. The term "acid chloride" is used because they are formed when an acid reacts with a chloride. Similarly, acyl bromide is formed when an acid reacts with a bromide, and acyl fluoride is formed when an acid reacts with a fluoride. The different names are used to describe the same type of functional group in organic chemistry. Despite having different names, all of these compounds have similar chemical properties and reactions.