Materials are used in conjunction with Mesh Renderers, Particle Systems and other rendering components used in Unity. They play an essential part in defining how your object is displayed.
The properties that a Material’s inspector displays are determined by the Shader that the Material uses. A Shader is a specialized kind of graphical program that determines how texture and lighting information is combined to generate the pixels of the rendered GameObject onscreen. See the documentation on Shaders for in-depth information about how Shaders are used in a Unity Project.
The standard Shader presents you with a list of material parameters. You can use these parameters to recreate the look of almost any real-world surface. For in-depth information on these material parameters, see the Material Parameters documentation.