What is the definition of a die in the context of casting?

In the context of casting, a die refers to a specific type of mold that is typically made of metal and used to shape molten materials, particularly metals. When casting, molten metal is poured into the die, where it solidifies to form a specific shape or component once cooled. The use of dies in casting allows for high precision and the ability to produce complex geometries in manufacturing processes. This makes option B the accurate definition in relation to casting.

Other options do not pertain to the definition of a die in casting. A high-speed tool is not directly related to the process of shaping molten materials. A cooling system may be involved in the casting process, but it does not define what a die is. Similarly, while a measuring instrument plays an important role in ensuring precision in engineering and manufacturing, it does not encapsulate the notion of a die used for shaping materials in casting.