How does interior design differ from interior decoration?

While the terms are sometimes used interchangeably in casual conversation, there is a professional distinction between interior design and interior decoration.

Interior design is a specialized branch of architecture and environmental design that involves the planning and supervision of man-made spaces. It addresses the aesthetic, functional, and psychological aspects of a space, focusing on the intimate scale of design and the individual character of interiors. Because it is a professional field, interior designers often work within complex, contractual frameworks, particularly in nonresidential or "contract" design, where they coordinate with architects and other specialists to manage structural and environmental elements.12

In contrast, the term "interior decorator" has been applied so loosely since the mid-20th century that it has become less descriptive of the professional, technical scope associated with interior design. Historically, residential interior decoration has often been associated with commission-based work rather than the formal, systems-oriented approach of professional interior design. While some dictionaries define the terms as synonymous, the professional field of interior design is distinguished by its broader scope, technical complexity, and its status as a serious, established profession.21345