Architecture is one of those overloaded terms in the software industry that has been so abused that we should consider scrapping it and coming up with a new words to replace it. However, that isn’t going to happen anytime soon; so, we’ll have to try to recover this one.

I recently came across Grady Booch’s definition of architecture, and I really like it…

All architecture is design but not all design is architecture. Architecture represents the significant design decisions that shape a system, where significant is measured by cost of change. –Grady Booch

This succinctly captures what I think makes for good architectures and good architects. The best architects have good judgment and intuition, based on experience, about what the most important design decisions are. They recognize which aspects of a system they’ve got to get right from the start and which can be firmed up later. They focus on the design decisions that would be costly to change later.