Architecture is defined by the recommended practice as the fundamental organization of a system, embodied in its components, their relationships to each other and the environment, and the principles governing its design and evolution.
[ANSI/IEEE Std 1471-2000, Recommended Practice for Architectural Description of Software-Intensive Systems]

"All the choices and challenges facing the modern software architect are staggeringly intertwined. Each of them both constrains the others and affects multiple key outcomes. Minor decisions often have huge implica- tions. As in the physical world, this is the difference between engineering and architecting." IEEE Software,2016 nov.

Philippe Kruchten put it, “The life of a software architect is a long and rapid succession of suboptimal design decisions taken partly in the dark.” IEEE