Calcium oxide, also known as quicklime, has several synonyms that can be used interchangeably. Some of the commonly used synonyms for calcium oxide include burnt lime, unslaked lime, lime, and caustic lime. Burnt lime is a term used to describe the process of heating calcium carbonate, resulting in the formation of calcium oxide. Unslaked lime refers to the fact that calcium oxide reacts with water to produce calcium hydroxide, which can be used in various applications. Lime is a broad term used to describe various compounds of calcium and is used in several industries, including construction, agriculture, and chemistry. Caustic lime is a term used to describe the strong alkaline properties of calcium oxide, which makes it ideal for several industrial applications.