Our universe is made up of a whole lot of systems that function together. For this to happen smoothly, there has to be a certain equilibrium (both inter and intra-system) that should be attained. This gives rise to a stable structure within the system.
A structure is essential in all forms of design.
Structure and Patterns
Structures and patterns are very similar, yet are unique. A pattern has structure, but all structures may not have a pattern. Patterns can be easily dismissed as structures, and vice versa. I believe that structures are based on pre-existing patterns. The may not be a pattern in themselves, but they do follow a certain pattern, hence becoming a structure.
Structure in Design
In design, structure exists in almost every dimension, and in both, tangible and intangible form. For instance, for a product to be stable, the structure has to be stable for it to work with ease (3D structure). It has to be aesthetically pleasing (a mental structure), and during the promotion/ marketing/presentation of the product, there are certain 2D structures which show up- colour schemes, layouts, hierarchy, etc., which are all types of structures.
When an audience receives information and processes it, it happens structurally; certain biological structures and psychological structures emerge.

