What term describes an interior recess created in a workpiece?

The term that best describes an interior recess created in a workpiece is "pocket." In machining and metalworking, a pocket refers specifically to a hollow area within the material, which is often designed for a specific purpose such as to reduce weight, provide space for other components, or facilitate assembly.

Pockets can vary in shape and size, depending on the requirements of the design or function of the workpiece. They are typically created through processes such as milling or CNC machining, where the cutting tool removes material from the interior of the workpiece to achieve the desired recess.

In contrast, other terms like "groove," "cavity," and "notch" describe different types of features. A groove is a long, narrow indentation that runs along the surface of the material, while a cavity may refer to a broader, often deeper empty space but does not specifically imply being interior unless stated. A notch usually indicates a small cut or indentation at the edge or corner of a workpiece rather than a recess that extends into the material. Thus, pocket most accurately captures the concept of an interior recess in this context.