As a passionate advocate for the body of knowledge that is at the core of the interior design profession, the Council for Interior Design Accreditation (CIDA) stays closely attuned to the changing nature of the practice of interior design. To this end, CIDA endorses the following definition of interior design, approved in July 2004 by the Board of Directors of the Council for Interior Design Qualification (CIDQ). Because the practice of interior design has grown as technology and the environment have evolved, CIDQ believed a new definition was needed to better reflect the changes taking place in the profession. A task force of interior designers from the United States and Canada developed the new definition and presented it for review and comment by all CIDQ member boards and members of the major interior design organizations and associations.
You might also be interested in the CIDQ definition of interior design: www.cidq.org/definition-of-interior-design.