What is a "blueprint" primarily used for?

The term "blueprint" primarily refers to a detailed plan or design for something, often associated with architecture and engineering where it outlines the specifications and arrangements of a building or structure. Blueprints provide precise measurements, layouts, and details necessary for construction, serving as a critical tool to guide the building process.

This choice effectively captures the essence of what a blueprint represents—thorough planning and careful design, rather than a superficial or vague outline. While other options refer to different forms of planning or representation, they lack the specificity and detail inherent in a blueprint's purpose and function.