A graduate certificate or diploma (the terms are used interchangeably in North America) in design denotes specialization in a sub-field or discipline of design gained through intensive graduate-level study. As such, it supplements an already established area of expertise (in design or not related to the field) and adds value to a previously earned Bachelor's or graduate degree. Delivered in various formats from residential to online, graduate certificates in design comprise 4 - 6 courses (typically 12 - 18 credit hours) taken in a prescribed sequence at the graduate level.
The concurrent graduate certificate or diploma in design allows students currently enrolled in a Master's or Doctoral degree program in the field to pursue an in-depth exploration of one aspect of their field. For example, a student working towards a Master's in Design with a specialization in Fashion may take the Graduate Certificate in Merchandising to augment their expertise.
The stand-alone, direct-entry graduate certificate/diploma program in design provides an opportunity for graduate-level study of theory and research to students who are not interested in pursuing a full graduate degree. This could include professionals with a Bachelor's degree working in the field or anyone who does not have the time or interest in a traditional graduate program in design. Then too, some students who take the stand-alone certificate already have a graduate degree and use their certificate to augment a particular area of interest.
A selection, but not inclusive list, of graduate certificates/diplomas in design includes

Graduate Certificate in Apparel Design

Graduate Certificate in Ceramic Arts

Graduate Certificate in Fashion Studies

Graduate Certificate in Graphic and Digital Design

Graduate Certificate in Material Culture Studies

Graduate Certificate in Merchandising

Graduate Certificate in Interior Design