structure is a noun that is used to refer to the way that something physical or abstract is assembled or put together. This includes things like building and machines as well as relationships, systems, and rules. It can refer both to how something is built or organized, or simply the shape or arrangement of it.
1. The structure of the house was impressive.
2. I was impressed by the structure of the essay.
3. The structure of our government is quite unique.
the word structure can sometimes be confused with the word arrangement, but it is important to note that structure usually implies a fixed or ordered pattern, while arrangement tends to imply more of an element of choice or negotiation. Additionally, when using the plural form of structure (structures) it is usually used to imply material objects, rather than abstract things like relationships and systems.