Participatory design (originally co-operative design, now often co-design).
Is an approach to design attempting to actively involve all stakeholders (for example employees, partners, customers, citizens, end users) in the design process to help ensure the result meets their needs and is usable. Is focused on processes and procedures instead of a visual design.
Recent research suggests that designers create more innovative concepts and ideas when working within a co-design environment with others than they do when creating ideas on their own.
During a co-design session we talk about the different processes of our agenda, the users and their assignments, what they will see, what they can do, the proper device for the use of the agenda, etc.