In book design, a pre-made framework for a book cover or interior layout, intended to be used repeatedly to save time and increase consistency.
The advantage of template-based design is that it allows the designer to refine the template and become familiar with it over time, leading to a fast turnaround and consistent product.
The disadvantage of template-based design is that the results tend to be generic or even identical. The design process has been partly completed in advance and so cannot be fully customized to each job.
A template is not the same thing as a repetoire of practised techniques. All designers build up a palette of techniques which they call on to achieve specific effects. A template is an actual half-complete layout which the designer re-uses from one job to the next.