What term represents a detailed plan for a building?

The term that represents a detailed plan for a building is "blueprint." A blueprint is a technical drawing that provides precise details about the design, dimensions, and structural elements of a building, allowing architects and builders to construct the project according to specific specifications. This term is commonly used in architecture and engineering to convey the visual and technical information necessary for building construction.

In contrast, amity refers to friendship or peaceful relations between people or groups, which does not relate to architectural planning. Residual pertains to something that remains after a part is removed or dealt with, often used in financial or scientific contexts rather than in construction. Sect refers to a subgroup of a larger system, often in religious contexts, and does not connect to building plans. Therefore, the choice of "blueprint" as the correct answer aligns perfectly with the context of architectural design.