Form is the overall three-dimensional configuration or __________ of a design or composition.

The term "form" in the context of design or composition refers specifically to the overall three-dimensional configuration or shape of an arrangement. When discussing floral design, "form" encompasses the visual aspects that create the outline and structure of the arrangement, guiding how all elements relate spatially to one another.

"Shape," as the correct choice, accurately captures this concept because it deals with the contour and silhouette of the design, allowing for an understanding of how the arrangement will appear in space. By focusing on the outline and structure, the designer can create a balanced and visually appealing composition.

In contrast, while size pertains to how large or small the design is, it doesn't directly address the three-dimensional configuration. Texture relates to the surface qualities and feel of materials, which can influence the visual experience but does not define the overall structure. Lastly, pattern refers to the repetition of elements and visual motifs within the design, rather than its three-dimensional configuration. Thus, the emphasis on "shape" as it relates to "form" effectively aligns with the broader understanding of composition in floral design.