Which concept refers to the pleasing relationship between different parts and the whole in a design?

The concept that best refers to the pleasing relationship between different parts and the whole in a design is proportion. Proportion involves the scale and size of elements in relation to each other and the overall space, ensuring that a design feels cohesive and well-composed. When proportion is effectively achieved, each component fits naturally within the environment, contributing positively to the overall aesthetic and functionality.

This harmonious relationship helps create a sense of unity in the design. While balance, symmetry, and harmony are important concepts in design, proportion specifically focuses on the relative sizes and scale of elements, which directly impacts how they relate to one another and contribute to the overall composition in a way that feels visually satisfying.