A material's property is an intensive, often quantitative property of a material, usually with a unit that may be used as a metric of value to compare the benefits of one material versus another to aid in materials selection.
A material property may be a constant or may be a function of one or more independent variables, such as temperature. Material's properties often vary to some degree according to the direction in the material in which they are measured; a condition referred to as anisotropy. Materials properties that relate two different physical phenomena often behave linearly or approximately so in a given operating range and may then be modeled as a constant for that range. This linearization can significantly simplify the differential constitutive equations that the property describes.
Some material's properties are used in relevant equations to determine the attributes of a system a priori. For example, if a material of a known specific heat gains or loses a known amount of heat, the temperature change of that material can be determined. Materials properties may be determined by standardized test methods. Many such test methods have been documented by their respective user communities and published through ASTM International.