Blocked teaching means that individual modules of a semester are taught as a block and within a few weeks. This form of teaching differs from the “classic” teaching system when several courses are taught equally distributed throughout the entire semester.
In the block system, you can concentrate on just one assignment or topic during each course: teaching and the final exam (first attempt) for a module are completed before the next block starts. The workload is therefore more equally distributed and it is easier to remember the course content until the exam takes place.