This is part of my school work at Steven Institute of Technology. The assignment is to come up with a definition of a system architecture by my own words. Here it is:
A system architecture is the organization of a set of components forming up a system. It provides a plan that arranges the responsibilities of each internal component in the system and their interactions to each other as well as the interactions between the system and the external environment it resides and/or being operated in.
A system architecture also refers to a set of artifacts by which the plan of the system can be communicated to each other among stakeholders.
A complete system architecture includes a methodology guiding the instantiation activities of the system which also rendering a consistent style among system instances.
The last point about methodology is what I learned from my work experience, and inspired by the architecuture from civile engineering.