In numismatics, a matrix is an intermediate mould used in the process of manufacturing coins.
The use of a matrix lengthens the production of dies, but makes for a gain in consistency.
The creation of a matrix addresses the basic problem for the coinage of multiplying dies, i.e. having enough accurate copies of dies to produce long runs of essentially identical coins.
[1][2] The creation of a master punch from a matrix is called "hobbing".
[3] In contrast, a patrix is a type of master punch with a design in relief, used to create dies.