Code Structure regards the way that code is written to allow it to be best read, maintained and organized for efficiency. Decisions such as when classes should be used, and which patterns would be most efficient for a task.
This is a cross-language discipline that allows code to be read and maintained easier. In some areas, such as simple web design, this may relate simply to best practices, such as creating your CSS using a separate file, and then organising this in a way that makes the most sense (starting with a browser reset, then the structure, and then into areas such as fonts).
In more complex languages, however, this also involves the use of patterns to be most efficient, and removing duplicated code and overall making your application appear much simpler.
