The terms “tool” and “die” are used interchangeably to the point that many machinists refer to the field broadly as “tool and die”, regardless of their specific expertise. In general, this practice is completely appropriate—there is little functional difference between a tool and a die, if any, and most machinists who fabricate tools also create dies. However, there are some nuances to the terms in industry, so it’s worth breaking down the slight distinctions.