Indigo Carmine is a blue dye used in a variety of industries, including the food and textile industries. However, there are several synonyms for Indigo Carmine, including FD&C Blue No. 2, Indigo Blue, and Indigotine. These synonyms are often used interchangeably, but they all refer to the same compound with the chemical formula C16H8N2Na2O8S2. Indigo Carmine is commonly used as a colorant in foods such as candies, soft drinks, and baked goods, as well as in cosmetics and pharmaceuticals. Knowing the various synonyms for Indigo Carmine can help individuals working in the relevant industries better communicate and understand the uses and properties of this blue dye.