A phase diagram is a crucial tool in the study of material science and chemical engineering. It helps to illustrate the various phases of a substance in relation to temperature and pressure. However, there are several other terms used in different fields of science that describe the same concept as a phase diagram. For example, in geology and mineralogy, it is known as a stability graph or stability diagram. In physics, it is referred to as a Gibbs phase rule chart. In metallurgy, it is called an equilibrium diagram or a constitutional diagram. Regardless of the term used, they all depict the same crucial information about the composition and properties of materials.