When applied to architecture, design is both a noun and a verb. You can design a building?, and your building is a design. The operative notion is that design embodies the countless nights of thought, iteration and re-design, to approach a level of completeness that all parties can agree upon. In architecture this usually happens when the architect, client, building code inspector, and finally the construction? industry can agree to a finished design.
Design is not limited to architects: those in graphic design, art, web, and even [network administrators]? “design.”