Software architecture is the high-level structure of a software system, comprising the overall design and the fundamental organization of the system. It includes the selection of the hardware and software components and their interfaces, as well as the design of the system's overall structure and behavior. Software architecture plays a crucial role in the development of software systems, as it affects the performance, reliability, maintainability, and other important aspects of the system.

The SOLID design principles are a set of guidelines for writing maintainable and scalable software.