Définitions

Software architecture is 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. ¹

Architecture represents the significant design decisions that shape a system, where significant is measured by cost of change.

In most successful software projects, the expert developers working on that project have a shared understanding of the system design. This shared understanding is called “architecture.” This understanding includes how the system is divided into components and how the components interact through interfaces. These components are usually composed of smaller components, but the architecture only includes the components and interfaces that are understood by all the developers . . . Architecture is about the important stuff. Whatever that is.. ¹

An architecture is the set of significant decisions about the organization of a software system, the selection of structural elements and their interfaces by which the system is composed, together with their behavior as specified in the collaborations among those elements, the composition of these elements into progressively larger subsystems, and the architectural style that guides this organization – these elements and their interfaces, their collaborations, and their composition.¹