Which process is commonly referred to as three-dimensional printing?

The process commonly referred to as three-dimensional printing is known as Additive Manufacturing. This approach involves creating objects layer by layer, hence the term "additive," as material is added to form the final product. This contrasts with subtractive manufacturing, where material is removed from a solid block to create parts.

Additive Manufacturing encompasses various techniques, including rapid prototyping and stereolithography, which are specific methods within this broader category. However, the term "three-dimensional printing" is often used interchangeably with Additive Manufacturing because it emphasizes the layer-by-layer construction that characterizes 3D printing technology.

In summary, Additive Manufacturing is the correct answer as it encapsulates the essence of three-dimensional printing, which involves building up material rather than cutting it away.