"An architecture is a description of system structures, of which there are several (module decomposition,process, deployment, layered, etc.). Architecture is the first artifact that can be analyzed to determine how well its quality attributes are being achieved, and it also serves as the project blueprint. An architecture serves as the vehicle for communication, is the manifestation of the earliest design decisions, and is a reusable abstraction that can be transferred to new systems. These are the things we mean when we use the word architecture."

[Software Architecture in Practice, 2nd Edition By Len Bass, Paul Clements, Rick Kazman]