What is the original drawing or tracing referred to as?

The original drawing or tracing is referred to as a master copy because it serves as the primary reference point for creating any reproductions, modifications, or further developments of that design. In architectural and design contexts, the master copy embodies all the essential details and specifications that guide the creation of other representations, ensuring consistency and accuracy across various iterations. It represents the authenticity of the design, capturing the creator's intended vision and technical precision.

In contrast, terms like draft or final design represent different stages of the design process or variations but do not encapsulate the concept of an original reference. A draft may be an early version with possible changes, while a final design indicates a completed version, whereas a replica is simply a copy of an existing design rather than the original source. Therefore, "master copy" distinctly identifies the original work used for reproduction and reference.