Materials definitions are critical elements of ALL engineering functions, especially design, structural analysis and quality. Current methods of defining materials are substantially based on empirical testing approaches and require a categorization of materials into a single material entity, often defined by a specification. The current use of material specifications results in static definitions that provide the worst of the worst property capabilities for all of the materials deemed equivalent. Use of model-based tools for enhanced definition of materials can eliminate arbitrary categorization of materials and the very limiting minimum property capability limits. Model-based material definitions, though complicated offers an immense potential for advancing material applications, and component and system capabilities. The elements of a model-based material definition will be reviewed.