It's important to note that "lime" can sometimes refer to other related substances:

* Quicklime: This is the pure form of calcium oxide, which is a white, caustic solid.

* Hydrated lime: This is calcium hydroxide (Ca(OH)2), which is formed when quicklime reacts with water. It's also known as slaked lime.

* Lime mortar: This is a building material made by mixing hydrated lime with sand and water.

So, while "lime" can refer to several different things, the core chemical is calcium oxide (CaO).