What is the difference between Design and Architecture?
Think of it this way: for building a house, you get a blueprint from architect (Architect). Then constructor use this blueprint and makes decision (Designer) on how many columns are required what kind of cement and bricks to use, what type of coloring needs to be done etc. These are design decision. Then worker takes order from builder and construct the house (Coder).
See architecture and design.
The software architecture of a program or computing system is the structure or structures of the system, which comprise software components, the externally visible properties of those components, and the relationships between them. [...] Documenting software architecture facilitates communication between stakeholders, documents early decisions about high-level design, and allows reuse of design components and patterns between projects.
--
Software design is a process of problem-solving and planning for a software solution. After the purpose and specifications of software are determined, software developers will design or employ designers to develop a plan for a solution. It includes low-level component and algorithm implementation issues as well as the architectural view.
--
So they share parts with each other, but they refer to slightly different aspects of software. Technically speaking, architecture should include all aspects, but in reality they usually refer to high level topology or structure of software. For example, making decision about whether to implement a system as a file-based command line software, a web app, or an n-tier rich internet application would be an architectural decision.
Software design includes making architectural decisions, but it would include much deeper ones like how many characters address1 should be in a database, which is not really an architectural decision.
Edit: To simplify the difference, architecture refers to known patterns of software solution, often involving placement and relationships between subcomponents/tiers/layers. The patterns also specify how and where the data is stored, processed, and presented. An architecture is something that could be described using boxes and arrows, such as autonomous robotic paradigms.
The software design is a process of thinking about solutions to the given software requirements. Each problem is unique in its own ways, so design would be different.
In my understanding, design is more specific to one system. Two systems could have a similar design but share the same architecture.
So a design defines how a chosen architecture is applied to the given requirements. (or something like this)
But this is more a feeling of mine, so I'm interested in other answers ...