Solution architecture is a practice of defining and describing an architecture of a system delivered in context of a specific solution and as such it may encompass description of an entire system or only its specific parts. Definition of a solution architecture is typically led by a solutions architect.
There are many definitions of "solution architecture" in the industry but as of yet no official definition exists. The Open Group (2009) defined solution architecture as:
- A description of a discrete and focused business operation or activity and how IS/IT supports that operation. A Solution Architecture typically applies to a single project or project release, assisting in the translation of requirements into a solution vision, high-level business and/or IT system specifications, and a portfolio of implementation tasks. 
- A solution architecture (SA) is an architectural description of a specific solution. SAs combine guidance from different enterprise architecture viewpoints (business, information and technical), as well as from the enterprise solution architecture (ESA). 
- An architecture of a solution, where a solution is a system that offers a coherent set of functionalities to its environment. As such, it concerns those properties of a solution that are necessary and sufficient to meet its essential requirements
Most definitions agree that the distinguishing characteristic of a solution architecture is that its context is a specific solution or deliverable as opposed to an entire enterprise or a segment of an enterprise. Furthermore, definitions put emphasis on a very specific nature of solution architecture and on its alignment with higher-level principles and specifications.
Solution architecture topics
Typical outcomes of solution architecture
Solution architects typically produce solution outlines and migration paths that show the evolution of a system from baseline state to target state. A solution architect is often but not always responsible for design to ensure that the target applications, in a technical architecture, will meet non-functional requirements.
A solution architecture may be described in a document at the level of a solution vision or a more detailed solution outline. It typically specifies a system (itself usually a subsystem in a wider enterprise system) that is intended to solve a specific problem and/or meet a given set of requirements. It may be an IT system to support a single business role or process. For example, an end-to-end eCommerce system that allows customers to place orders for goods and services; or an end-to-end Supply Replenishment system that enables an enterprise to order new stock from its suppliers.
A solution outline typically defines the business context, business data to be created or used, the application components needed, the technology platform components needed, along with whatever is needed to meet non-functional requirements (speed, throughput, availability, reliability recoverability, integrity, security, scalability, service ability, etc.).
The term solution architecture is widely used outside of an enterprise architecture context. It is also used in some enterprise architecture (EA) frameworks, with particular meanings. In TOGAF it can mean the physical implementation of a logical architecture, or a detailed software architecture. In US government guidelines, it is pitched at the bottom level of a stack below "enterprise" and "segment" architectures, as shown in the diagram below.
In other contexts, a wide range of stakeholders, even business owners, may be concerned to review a solution vision or solution outline and monitor progress towards implementation.
Relationship with enterprise architecture
Relationship between enterprise architecture and solution architecture is generally well understood. According to the 2013 paper published by the Federation of Enterprise Architecture Professional Organizations, solution architecture includes business architecture, information architecture, application architecture, and technology architecture operating at a tactical level and focusing on the scope and span of a selected business problem. In contrast, enterprise architecture, which also includes aforementioned four types of architecture, operates at the strategic level and its scope and span is the enterprise rather than a specific business problem. Consequently, enterprise architecture provides strategic direction and guidance to solution architecture. 
- The Open Group. Architecture Framework TOGAF™ Version 9. 2009. p. 93
- Gartner, "IT Glossary," at gatner.com, 2013. Accessed 00-03-2015.
- Danny Greefhorst & Erik Proper, Architecture Principles: The Cornerstones of Enterprise Architecture, 2011. p. 25
- Martin Fowler. Patterns of enterprise application architecture, 2012.
- FEAPO, "A Common Perspective on Enterprise Architecture" in: Architecture and Governance Magazine, 2013(11).
- Mistrík Ivan, Antony Tang, Rami Bahsoon, Judith A. Stafford. (2013), Aligning Enterprise, System, and Software Architectures. Business Science Reference.
- Banerjee, Jaidip, and Sohel Aziz. "SOA: the missing link between enterprise architecture and solution architecture." SETLabs briefing 5.2 (2007): 69-80.
- Chen, Graham, and Qinzheng Kong. "Integrated management solution architecture." Network Operations and Management Symposium, 2000. NOMS 2000. 2000 IEEE/IFIP. IEEE, 2000.
- Gulledge, Thomas, et al. "Solution architecture alignment for logistics portfolio management." International Journal of Services and Standards 1.4 (2005): 401-413.
- Shan, Tony Chao, and Winnie W. Hua. "Solution architecture for n-tier applications." Services Computing, 2006. SCC'06. IEEE International Conference on. IEEE, 2006.
- Slot, Raymond, Guido Dedene, and Rik Maes. "Business value of solution architecture." Advances in Enterprise Engineering II. Springer Berlin Heidelberg, 2009. 84-108.
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