If you need to distinguish between the process of designing the system or software architecture from the design of the system of software components, then you can use "architectural design," otherwise "design" is a perfectly valid and descriptive word.
When I shared this complaint with my Mother the architectural engineer, she agreed with me completely. In her career, she never once heard any of the architects refer to what they were doing as anything other than designing. An architect designs architecture. That is true for buildings and software based systems.